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Transcritical R744 (CO2) heat pumps - Technician Manual

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1. nh HET HE Ed di Hu Lg T ar z LUPA AU c 53 a a E LL a Sond D FO 46 am BO 100 180 140 6 180 PC zn ra zai F0 at A asi 169 2m a change scala Enthalpy kd kg above saturated tiqui at 400 Figure 5 A subcritical cycle using R22 Traditional refrigerants have been chosen or designed so that they can be condensed with an available cooling medium often water or air This requires that their critical temperature be well above the temperature of the cooling medium 1 e typically in the range 80 110 C Refrigerant R22 for example will yield a thermodynamic cycle that could be illustrated by Figure 5 The R22 critical temperature is 96 2 C This means that with water or air available at 40 C R22 may condense at say 55 C Because there exists a unique relationship between pressure SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 13 62 SHERHPA Sustainable d and Energy Research ws C CETIA E T I A T for Heat Pump A plications Rapport 2414173 October 2007 and saturation temperature for a condensing pure substance its pressure will be 21 8 bars abs Note that for a given installation this condensing pressure will in practice depend mainly upon the following parameters e The water or air flow rate and available temperature e The charge of refrigerant into the system and the condenser size In this installation the refrigerant flow rate is controlled by the expansion device
2. o 330 ester no a Natural refrigerants propane isobutane mE pm R744 5 2 bars LS pepe pe9 m ammonia I reference R11 2 azeotrope or quasi azeotrope 3 average of dew and bubble point temperatures However as of year 2007 there is virtually no ideal alternative to the current HFC refrigerants and provided all the technological challenges are dealt with in terms of safety equipment mechanical resistance to working pressures flammability etc natural refrigerants seem to be the most viable options particularly in heat pumping equipment The applications of some natural fluids are discussed below while a specific section will be devoted to carbon dioxide SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 7 62 SHERHPA Sasteinabin Heat and Energy Research ES CETIA E T I A T for Heat Pump A plications Rapport 2414173 October 2007 1 3 1 Isobutane R600a Isobutane is a hydrocarbon and hence is flammable With thermodynamic properties that are very similar to those of R134a isobutane was used in Germany as early as 1992 to replace R12 It is nowadays used in the great majority of domestic refrigerators These appliances require small refrigerant charges typically 70 to 150 g and are hermetic Hence no accident has been reported so far in these household applications Isobutane presents other advantages such as its compatibility with mineral oil and better ene
3. temperature from the gas cooler evaporating temperature or air outdoors temperature provide the best control system These controls are implemented in the Ecocute unit and the Stiebel Eltron heat pump If transcritical operation at fixed pressure is possible Danfoss proposes two pressure regulators e A manual pressure regulator the pressure can be set manually on the valve MBR e An automatic back pressure regulator which uses the gas cooler outlet temperature to control high pressure BPR Manual Back Pressure Regulator Function The spring loaded membrane is opening the M BR downstream orifice once the inlet pressure acting on the membrane is high enough to overcome the spring force Cap Pressure adjustment Remove the cap and adjust the opening pressure by changing the spring force by turning the adjustment screw This process is possible under valve operation Initial pressure setting is 90 bars Do not exceed a inlet pressure setting of 120 bars LL Opening pressure adjustment Flow direction out indication Membrane Orifice Figure 42 Danfoss MBR regulator for transcritical R744 systems These two valves are shown in Figures 442 and 43 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 35 62 SHERHPA for Heat Pump Applications A Rapport 2414173 October 2007 Thermal Back Pressure Regulator Function The orifice membrane is opening the downstr
4. Performance vs Discharge pressure Figure 7a shows a cycle operated at a given value of high pressure At this value the system requires a heat input q at the evaporator and a work input w to the compressor The delivered heat duty at the gas cooler is therefore g w Under these conditions the R744 refrigerant at exit of the gas cooler reaches a temperature T If the cycle is operated at a different values of high pressures and a constant value of temperature T both q and w will vary and so will the value of COP Figure 7b shows the variation of COP when the high pressure is allowed to vary It can observed that there exists a value of pressure called optimal pressure for which the COP is highest Thus the most efficient heat pumps will use control schemes that enable high pressure control during operation However some systems also use simpler methods such as expansion through a capillary tube or some simple control scheme that enables operation at fixed high pressure As a rule of thumb the optimal pressure is approximately given by the following equation pt 2 OF 8 exit SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 16 62 pu SHERHPA AY L A Sustainable Heat and Energy Research C C E T I A T d Js Le F ati I Rapport 2414173 October 2007 where Pop is expressed in bars and Texi is the R744 temperature in C at exit of the gas cooler Thus a gas c
5. Side view 1 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 22 62 SHERHPA Sustainable Heat and Energy Research for Heat Pump Applications CETIAT aa eee Rapport 2414173 October 2007 These chillers can be operated either under sub critical or transcritical conditions Figures 12 to 15 show pictures of an Atlantic chiller Figures 12 and 13 show the control panel the compressor rack 3 black units and the R744 high pressure tanks in green ed Figure 16 Atlantic chiller back view Figure 17 Side view 2 Annex 2 shows the Green and Cool Atlantic product range with a performance table The Atlantic product range is normally equipped with air cooled gas cooler not shown in Figures 12 to 15 and can handle duties up to 200 KW depending on the evaporating temperature Green and Cool sources finned coils gas coolers from other manufacturers The Green and Cool Atlantic is a liquid chiller unit that is available as an air conditioning unit HT a chiller unit MT and a freezer unit LT with a partially indirect system On the cold side the HT uses water for air conditioning the MT uses 37 Propylene glycol solution for chilling applications and and the LT uses R744 as the heat transfer medium for freeze units 3 3 Vending machines and bottle coolers Transcritical R744 cycles are also used for small commercial refrigeration systems The Coca Cola Company TCCC has pledge
6. The tap water from the main SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 18 62 SHERHPA Sustainable Heat and Energy Research ay C5 CETIA E T I A T for Heat Pump Applications Rapport 2414173 October 2007 water supply is fed to a coil inside the tank It is then heated and routed to the different taps kitchen shower etc Supplemental electrical heaters inside the tank allow for an increase in water temperature if the heat pump does not provide sufficient heating 60 C y Radiator for Space Heating 1 Heat Pump unit Tank unit Water Supply Figure 9 Flow diagram of the Sanyo Ecocute www sanyoaircon com Table 3 shows the claimed performance of this product depending on the water tank model electrical input 3 phase and single phase DAIKIN Note that this unit 1s claimed to work down to 2002 2 outdoors temperatures of 15 C without loss mie in heating duty Various Ecocute models from other manufacturers are shown in Figure 10 A Hitachi model shown in Figure 10 is made MATSUSHITA 2003 11 up of two units connected in series This heat pump does not have a large tank It produces instant hot water and is not intended for space heating It is designed to be installed outdoors thus saving indoors space Figure 10 Various Ecocute models www heatpumpcentre org SHERPHA PROJECT Transcritical R744
7. e g capillary tube thermostatic expansion valve electronic expansion valve This device controls the amount of superheat at the suction of the compressor and ensures that no liquid droplets are carried out from the evaporator Put shortly heat pumps using traditional fluids such as HFCs and HCFCs operate with e condensing pressures that depend only on cooling medium conditions and on the refrigerant charge The condensing pressure is much lower than the refrigerant critical pressure So far R410A 1s the refrigerant that required the highest operating pressure its upper limit being roughly 40 bars e Refrigerant flow rates that are controlled via an expansion device in order to avoid carry over of liquid droplets to the compressor suction The expansion device set point is a value of superheat at compressor suction 2 2 2 Heat pumping with R744 the transcritical cycle As mentioned previously the critical temperature of R744 is around 31 C If ambient air is used to cool on the high pressure side and is available at 35 C for example it will not be possible to condense the refrigerant Rather the refrigerant discharged from the compressor will be cooled as a supercritical fluid because this process occurs at a pressure higher than the critical pressure 74 bars Such a cycle is illustrated in a Mollier Diagram in Figure 6 In this illustrative cycle R744 evaporates at 30 bars and is then compressed to 120 bars Upon co
8. upon cooling below P 6 bars Refrigerant state standstill Partly liquid and partly vapor At least 74 bars can be higher depending on charge and temperature System pressure standstill Refrigerant vapor pressure at T ambient gt 31 C ambient air temperature 3 R744 HEAT PUMPS TECHNOLOGY In Section 2 the basics of the transcritical cycle were examined In this section some R744 applications both for cooling and or heating will be surveyed with a focus on the SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 17 62 Um SHERHPA Sustainable d and Energy Research won CETIA E T I A T for Heat Pump A plications Rapport 2414173 October 2007 technology of the components Only applications which are marketed or are at a noteworthy stage of development as of year 2007 will be included herein Industrial applications air conditioning and mobile air conditioning systems will not be covered Marketed applications cover e Tap water heating e Space heating e Chilled water for air conditioning e Commercial refrigeration positive and negative temperature levels While the water heating applications have been marketed only in Japan some commercial refrigeration and air conditioning applications have been commercialized in Europe During 2007 a few Japanese heat pumps have been installed in Europe mainly in Sweden for tap water heating and residential hea
9. En DE A CE CN IT EU SR ee ON EVA ET ET DT EU 59 IE D OPK MT EX Cf QUES ET ET END M BE PA ee ca ON D ET 24 9A Oe Figure 2 Pressure Temperature phase diagram of R744 Danfoss SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 10 62 SHERHPA NL Sustainable Heat and Energv Research C C E T I A T for Heat Pump Applications R744 RAMA R410A 30 C 3E 20 C 15 C 10 C Sg QC Temperature Figure 3 Comparison of evaporating pressures Note that below a pressure of 5 2 bar solid and gaseous R744 phases may co exist at low temperature This behavior is totally different from that observed with traditional refrigerants and will have important consequences on the operation servicing and maintenance of a system working with R744 Figure 3 compares the evaporating operating pressures of R744 to those encountered with R410A and R404A It can be observed that R744 systems will require to operate a much higher pressures than conventional systems SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 11 62 SHERHPA Sustainable Heat and Energy Research k for Heat Pump Applications COCETIAT Rapport 2414173 October 2007 1000 100 a oa I th i amp i r4 TT e I d c 10 Copyright 1938 Chemical ogic Corporation www chemicalodic cam 300 100 500 400 Figure 4 R744 Mollier Diagram SHERPHA PROJECT Transcrit
10. SHEET Revised edition no 1 Date 15 7 2005 Supersedes 0 0 0 Carbon dioxide AL018A 10 STABILITY AND REACTIVITY Stability and reactivity Stable under normal conditions 11 TOXICOLOGICAL INFORMATION Toxicity information In high concentrations cause rapid circulatory insufficiency Symptoms are headache nausea and vomiting which may lead to unconsciousness 12 ECOLOGICAL INFORMATION Ecological effects information Global warming factor CO2 1 13 DISPOSAL CONSIDERATIONS When discharged in large quantities may contribute to the greenhouse effect 1 General 14 TRANSPORT INFORMATION Do not discharge into any place where its accumulation could be dangerous To atmosphere in a well ventilated place Discharge to atmosphere in large quantities should be avoided Contact supplier if guidance is required UN No H I nr ADR RID Proper shipping name ADR Class ADR RID Classification code Labelling ADR Other transport information 1013 20 CARBON DIOXIDE 2 2 A Label 2 2 Non flammable non toxic gas Avoid transport on vehicles where the load space is not separated from the driver s compartment Ensure vehicle driver is aware of the potential hazards of the load and knows what to do in the event of an accident or an emergency Before transporting product containers Ensure that containers are firmly secured Ensure cylinder valve is
11. T for Heat Pump Applications Rapport 2414173 October 2007 The RKX26 31 semihermetic compressor takes advantage of a new design with 6 radial pistons This enable a slimmer version than the HGX2 series The motor is gas cooled in 2 or 4 pole version 3000 1500 rpm maximum speed of 3600 rpm With a swept volume of 31 cc it enables a displacement volume of 2 60 m hr to 6 70 m h This compressor can be mounted both in horizontal and vertical positions It uses Bock C120E Synthetic Oil has an integrated oil separator and HP LP safety valves Danfoss offers small displacement volume compressors see Figure 23 with capacity ranging from about 500 W to 2 kW Figure 24 shows the claimed performance for the product range The size 1s about the same as those used in domestic refrigerators i e from to 3 cc displacement volume These compressors are used in some of the Coca Cola vending Figure 23 Danfoss R744 compressor machines refrigeration cassettes www danfoss com Power CA ity W COP W Evaporating temperature C amm 1 7 ee A z e riz M33 1612 1711 2031 2 Test conditions Discharge pressure 90 bar Gas cooler outlettemp 20 C Suction gas temperature 20 C Ambient temperature 32 C Figure 24 Danfoss compressors characteristics SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 26 62 SHERHPA VA Sustainable Heat and Energy Research C C E
12. T I A T XD a ee for Heat Pump Applications Rapport 2414173 October 2007 The Brazilian manufacturer Embraco makes reciprocating compressors see Figure 25 with displacement volumes that are within the same range as the Danfoss series 1 to 3 cc Figure 26 shows the claimed refrigeration performance for these compressors For heat pumps the Embraco range of compressors enable a maximum heating duty of about 2 7 kW at 50 Hz Figure 25 Embraco R744 compressor Application Compressor Voltage Frequency ss Sons Rire EK2140CD 220 240V 50Hz EK2178CD 4 Quarter 2007 1 Quarter 2007 EK6160CD 100V 50 60Hz 1 i 2 Quarter 2007 EK 210CD 100V50 amp gs INIM 4 Quarter 2007 EK 217CD 100V 50 amp 0Hz 1 3 00 19 4 Quarter 2007 EK6210CD 115V 60H 1 423 YQuorej 2008 EK6217CD 115V 60H 1 34 482 2 Quarter 2008 Estimated Dota Test Conditions Evaporating ischarge eturn Ga Ambient Approach _ aun reum SMPO err Temperature Temperature CCF F ch CCR 23 3 10 Figure 26 Embraco R744 compressor product line The Italian manufacturer Dorin markets a range of compressors for transcritical operation With displacement volumes from 3 5 to 12 6 m hr Dorin covers the largest range of duties available on the market SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 27 62 for Heat Pump Applications SHERHPA VA S
13. shows the air R744 concentration in the air in percent should the entire cylinder spill into the room Table 6 Linde Gas R744 pressurized cylinders Cylinder R744 kg m3 1 atm 20C in air in 120 m3 workshop 11 20 Table 6 shows that cylinder B30 reaches the lethal limit of 9 However the calculation shown in Table 6 assumes a uniform spread throughout the workshop Since R744 1s heavier than air relative density of 1 52 it will stagnate in lower parts Thus even spills from cylinders B20 and B30 can be dangerous Spills from the mini cylinder can cause health problems see Table 4 It is therefore recommended to store R744 cylinders in ventilated areas If R744 is charged directly from the cylinder into the system with compressor being shut down the following will happen SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 46 62 gU TAN SHERHPA VACETIAT H s Sustainable Heat and Energy Research DES L 5 for Heat Pump Applications a eee _ LI gt n 3 T he Se A Rapport 2414173 October 2007 e the cylinder pressure will progressively decrease After a small number of recharges the cylinder pressure decreases It will not be sufficient to charge refrigerant when the system pressure reaches the R744 vapor pressure the cylinder will not be fully exploited and part of refrigerant will be left in the cylinder and wasted e the efficiency of c
14. the heat pump via a safety valve or when discharging R744 from a system care must be taken not to deteriorate equipment by dry ice In particular when evacuating R744 avoid pipe lengths that could be plugged by dry ice formation due to pressure expansion 6 1 2 Recharging R744 heat pumps When servicing heat pumps refrigerant recharging for conventional refrigerants HFCs and HCFCs is carried out using the value of nominal charge and the following information e the values of high pressure and subcooling after the condenser and or superheat at compressor suction e the refrigerant state before expansion view through a liquid line sight glass when available SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 44 62 SHERHPA Sustainable d and Energy Research ws C CETIA E T I A T for Heat Pump A plications Rapport 2414173 October 2007 Transcritical R744 heat pumps are fundamentally different because e there is no distinction between liquid and vapor phase before expansion e there is no value of subcooling after the gas cooling process because subcooling does not exist as such e the relationship between high pressure and refrigerant charge in the system is more complex than for conventional refrigerants Transcritical R744 domestic systems are normally factory charged The refrigerant charge has numerous effects particularly on the value of the compressor discharge pressure Inappropria
15. CSCETIAT Auteur Ahmed BENSAFI Bernard THONON Diffusion Confidential Date October 2007 Rapport 2414173 Transcritical R744 CO heat pumps Technician s Manual CENTRE TECHNIQUE DES INDUSTRIES AERAULIQUES ET THERMIQUES Domaine Scientifique de la Doua 25 avenue des Arts BP 2042 69603 Villeurbanne Cedex France T l 33 0 4 72 44 49 00 Fax 33 0 4 72 44 49 49 www cetiat fr E Mail cetiat commercial cetiat fr Livraisons Domaine Scientifique de la Doua 54 avenue Niels Bohr 69100 Villeurbanne Siret 775 686 967 00024 Ape 731 Z SHERHPA TK Sustainable Heat and Energy Research CA C E T I A T for Heat Pump A plications TABLE OF CONTENTS k NATURAL REFRIGERANTS recien ine0eco0e ones cura usto saeua eos oe A 4 LI Refrigeration and heat pumping i ases nd ed 4 1 2 A brief history of refrigerants eene 5 1 3 Natural refrigerants applications ss 6 Weill A SO DU CAINS CIR OO CENT BS O E d rU E E E SO RE EEEN o NEG 3 6 PO zz ea decorates 9 PNE LUI ERR TU T m 9 2 2 Comparison of subcritical and transcritical cycles 13 2 2 Characteristics of subcritical cycles Rs 13 2 2 2 Heat pumping with R744 the transcritical cycle 14 2 3 Optimum pressure with the transcritical cycle 15 2 4 Transcritical cycle vs Traditional Cy Cle 2 en 17 3 R744 HEAT PUMPS TECHNOLOGY esses 17 3 1 The Ecocute system for tap water and heating 18 3 2 G
16. HA PROJECT Transcritical R744 Heat Pumps Technician s Manual 3 62 SHERHPA Sustainable Heat and Energy Research 3 CETIA E T I A T for Heat Pump Applications Rapport 2414173 October 2007 1 NATURAL REFRIGERANTS I I Refrigeration and heat pumping Refrigeration and heat pumping effects can be produced via various processes In this document we will focus on the use of the vapor compression cycle which has been the workhorse of the refrigeration industry for well over a century Figure 1 shows the components of such a cycle in an air to air application Figure 1 Components of a refrigeration heat pumping cycle This thermodynamic cycle consists in the compression of a vapor the refrigerant also called working fluid followed by its liquefaction at a high pressure during which the working fluid rejects heat to a medium often air or water This produces a heating effect which is exploited in heat pumps Following liquefaction the pressure 1s lowered through an expansion device The resulting vapor liquid mixture 1s then evaporated at low pressure while taking up heat from a medium and hence producing a cooling effect which is used for refrigeration The vapor is then compressed to complete the cycle In the so called traditional cycle which may use HFCs of HCFCs the liquefaction process occurs below the critical temperature of the refrigerant hence the name of sub critical cycle This requires that
17. Heat Pumps Technician s Manual 19 62 IE eS SHERHPA UA SSS Pw Fia Heat and Energy Research CA C E I I A I c for Heat Pump A plications Papper 2414173 October 2007 Table 3 Sanyo Ecocute Performance www sanyoaircon com Performance _ _ _ _ S S S EE Power supply Heatpumpunit V 220 280 2240 amp _ po Tank unit V 400 84N 230 3 N Wexmumcured 0 Tankunit G Tank capacity o O 223 Auxiliary electric heater capacity kW 90 705 AX Shipment H W D mm 1736x700x737 Heat pump unit e 7 S pmenHWD mm 765x943x488 Figure 11 Hitachi catalogues shows the installation configuration for this model Note that Hitachi also sells classical Ecocute models with a separate water tank PE LE LE ME PAM TT m rump OEmEEC ELA am EME AAE a EUM mS Y Same isse 4 BORA DE Are AACR Ke mancament 00 Sk moesau esr Suramcaster liitentoncesste Figure 11 Hitachi Ecocute model SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 20 62 SHERHPA VA Sustainable Heat and Energy Research C C E T I A T for Heat Pump Applications Rapport 2414173 October 2007 To avoid water freezing between the tank and the heat pump the water temperature in the pipe connections is controlled via an outdoor temperature sensor This sensor will activate heat pump opera
18. TY GUIDELINES WHEN USING R744 IN HEAT PUMPS Section 2 1 provided some basic physical and thermodynamic data of R744 that were used as background information to understand the transcritical cycle operation This Section will provide more information and safety guidelines regarding the practical use of this refrigerant Annex 3 contains a Safety Data Sheet from a main R744 producer which should consulted for safety precautions for this refrigerant Transcritical heat pumps are not fundamentally different from subcritical heat pumps Hence all usual basic safety precautions taken for the operation of conventional heat pumps equally apply to R744 heat pumps Some additional rules will be introduced by the transcritical cycle distinct features which are the higher operating pressures and temperatures the specific control schemes and the use of R744 as a refrigerant 5 1 R744 effects on health Gaseous R744 is colorless and odorless at low concentrations NFPA RATING It is not flammable It 1s stable under normal conditions but can become dangerous if inhaled at concentrations roughly around 2 Due to the fact that it 1s odorless it is not self 444 alarming in case of leaks from systems Table 4 summarizes the effects and symptoms related to R744 inhalation depending on its concentration in the air OTHER Table 4 Effects of R744 on human health Effects and Symptoms 50 increase in breathing rate 10 Minutes short term exposu
19. al heat pum p manager All essential circulation pumps for heating anc DHW as well as the booster heater for a mono energetic heating operation are already integrated as standard The most important features Ideally suited to new build Optimised for the combined heating of the heating water anc DHW Maximum flow temperature 70 C Compact heat pump section for installation on an external wall 200 DHW cylinder Natural refrigerant CO2 Integral energy saving electronically regulated circulation pum p SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 48 62 SHERHPA Sustainable Heat and Energy m k CA C E T I A T a ene _ for Heat Pump Applications 2414173 October 2007 STIEBEL ELTRON HEAT PUMP Type Type Part na 221143 Height 650 rmm Width 820 mn WPL5N Depth 300 m m Output at A2 W35 5 KW r 11 EL JUL UP Avallable fi orm UCIOLDSr 200 HSE CN TSE Re Heat pump connection 1 2 Wicth cylincer module Depth cylinder module RR MM Height of unitwhen ited 00 Connection on the heating syster side 22 mim plug in con nector Preliminary specification SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 49 62 SHERHPA ACETIAT 2 ae Sustainable Heat and Energy Research S for Heat Pump Applications XA Rapport 2414173 October 2007 CTC AIR TO WATER HEAT PUMPS Air to water R744 heat pumps from CTC http www ctc
20. an s Manual 56 62 mmm K 9 gt for Heat Pump Applications CAS SHERHPA 7 A ET nx Sustainable Heat and Energy Research C C E T I A T Qu n c Rapport 2414173 October 2007 GREEN AND COOL PRODUCTS GREEN COOL green refrigeration systems ATLANTIC ATLANTIC is a liquid chiller unit for air cooled gas Options cooler condenser Superheat exchanger model HEI ATLANTIC is available as an air conditioning unit HT e Noise reduction a chiller unit MT and a freezer unit LT with a par eAntivibration mounts tially indirect system ATLANTIC has an air cooled gas e Flexible sleeves on the evaporator side and the cooler on the hot side and on the cold side the HT condenser side has water MT Propylene glycol 37 and thelTs use Flexible sleeves on the Heat exchanger R744 as the Secondary fluid Extra liquid reciver 62 liter ATLANTIC is designed for the refrigerant carbon dioxide Compressor oil R744 for the lowest possible environmental impact High temperature HT 280HT 3120HT 4150HT Chiller units Air Conditioning unit Partly indirect system Refrigerant R744 Refrigeration output kW 44 88 132 176 200 Compressor quantity 1 2 3 4 4 Secondary fluid Water Temp of Secondary fluid C In Out 12 7 12 7 12 7 12 7 12 7 Evaporation temperature C 2 2 2 2 2 Medium temperature MT 130 MT 260MT 390MT 4120MT Chiller units Chiller unit Par
21. ber 2007 Water Refrigerant Figure 36 Sanyo gas cooler Figure 37 Stiebel Eltron gas cooler Figure 38 Denso gas cooler Figure 39 Daikin gas cooler SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 33 62 SHERHPA p Sustainable Heat and Energy Research C E T I A T for Heat Pump Applications eI 2 ae Rapport 2414173 October 2007 4 4 Expansion devices and controls Transcritical heat pumps require high pressure control to minimize power consumption as covered in Section 2 3 This optimal pressure is a function of evaporating pressure or temperature and R744 gas cooler outlet temperature Figure 40 shows the location of a motorized control expansion valve a solenoid valve for defrost and of a pressure sensor in a typical Ecocute unit for hot water supply Figure 40 Control valves and pressure sensor in an Ecocute unit JKV Stepper motor expansion valves HPV Solenoid valve CCB Cartridge pressure control Figure 41 Control valves and sensor from Saginomiya The Ecocute units use electronic valves from Saginomiya as shown in Figure 41 Electronic expansion valves that use information from operating parameters water or R744 outlet SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 34 62 SHERHPA ACETIAT Sustainable Heat and Energy Research Cae m for Heat Pump Applications XA a eee Rapport 2414173 October 2007
22. closed and not leaking Ensure valve outlet cap nut or plug where provided is correctly fitted Ensure valve protection device where provided is correctly fitted Ensure there is adequate ventilation Compliance with applicable regulations 15 REGULATORY INFORMATION EC Classification EC Labelling Symbol s R Phrase s S Phrase s AIR LIQUIDE SA France Not classified as dangerous preparation substance Not included in Annex l No EC labelling required None None None SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 60 62 for Heat Pump Applications SHERHPA VA Sustainable Heat and Energy Research C C E T I A T X SAFETY DATA SHEET Revised edition no 1 Date 15 7 2005 Supersedes Q 0 0 Carbon dioxide AL018A Asphyxiant in high concentrations Keep container in a well ventilated place Do not breathe the gas Contact with liquid may cause cold burns frostbite Ensure all national local regulations are observed The hazard of asphyxiation is often overlooked and must be stressed during operator training This Safety Data Sheet has been established in accordance with the applicable European Directives and applies to all countries that have translated the Directives in their national laws Before using this product in any new process or experiment a thorough material compatibility and safety stud
23. d in the AC amp R industry Because of their nil contribution to ozone depletion these substances were promoted as the new miracle solution to the global environmental problems Kyoto 1999 HFCs are put in a basket of GHG substances However the HFCs have been listed amongst the substances contributing to global warming Greenhouse Gases GHG in the Kyoto Protocol in 1999 and the widespread use of these refrigerants is not expected to last This brief look at history shows that as refrigerants evolved no global approach has been adopted to simultaneously address the various issues mainly due to the lack of knowledge the effect of chlorine in the ozone layer was only discovered in 1975 but also because scientific evidence of the effects of refrigerants was not acknowledged So far mainly synthetic man made substances have been used as refrigerants and their environmental effects could only be identified on the long term Table 1 summarizes the properties and environmental impacts of some refrigerants This Table shows that no progress has been made in terms of global warming potential when switching from HCFCs to the HFC family With climate change becoming a major concern worldwide the use of HFCs will be regulated It is noteworthy that for automotive air conditioning applications the EC has already scheduled a progressive phase out of R134a as of year 2011 while limiting the GWP value of refrigerants to be used in ne
24. d to reduce to the lowest possible its uses of synthetic refrigerants As of year 2007 they operate 6000 transcritical vending machines with duties ranging from 300 W to a few kW SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 23 62 v SHERHPA VA Sustainable Heat and Energy Research C E C E T I A T X for Heat Pump A Applications Figures 18 and 19 show the cassette type refrigeration system working with R744 Figure 20 shows the product range potentially covered by transcritical cycles Heating Internal Heat Exchanger u UE LI High Fret ow Pria C ta Figure 18 R744 cycle components Figure 19 R744 Cooling cassette CDM1000 des PES 8 non ee ma gh me n RL LOUP ig T du y AF aeger ue Figure 20 Coca Coal vending machines range of products SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 24 62 nel a CACETIAT Sustainable Heat and Energy Research Fa L for Heat Pump Applications XA Rapport 2414173 October 2007 4 COMPONENTS FOR R744 HEAT PUMPS Components for R744 systems have to withstand much higher pressures than their HFC and HCFC counterparts Pressure differentials are higher by one order of magnitude Other issues are introduced by the particularity of R744 e g high discharge temperatures compatibility with lubricating oils potential degradation of seals af
25. doned in the mid 50s with the widespread use of the CFC refrigerants which were more efficient more stable and safer This section will summarize its physical properties and examine its particularities when applied as a refrigerant CO refrigerant will be referred to as R744 in the following 2 I Properties R744 is a versatile material being used in many processes and applications each of which takes advantage of one or more these characteristics reactivity inertness and coldness mostly when used in direct contact refrigeration Common uses include consumption as a raw material for production of various chemicals a working material in fire extinguishing systems carbonation of soft drinks freezing of food products chilling of meats prior to grinding refrigeration and maintenance of ideal atmospheric conditions during transportation of food products to market etc R744 is present in the atmosphere at concentration levels of about 380 ppm Exhaled air contains about 4 carbon dioxide At normal conditions it is gaseous R744 1s odorless at low concentrations and slightly toxic with a slightly pungent acid taste It is widely available as it occurs naturally and it is a by product of fossil fuel combustion and other industrial processes It combines with water in air to form carbonic acid which corrodes metals limestone and marble R744 will not burn or support combustion Air with a carbon dioxide content of more than 10 wil
26. e heat pump Do not attempt to disassemble and unit and do not iria hands c or EN unit ree ieu leave these jobs When snow has piled up remove it from Do pre si on the unit or apply force to and around the unit the pip Snow allowed to pile up on and around ihe An aided may oocur or you may bum heat Lamina and inku unit ind cause UU T yourself as a result SHP C45DEN Outdoor temperature versus oper the 4P terminal board of the heat pump unit DEM The unit is operating proper hy ifthe operating nurrent is within the shaded are SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 53 62 SHERHPA it N Sustainable Heat and Energy Research R C E T I A T X for Heat Pump Applications Rapport 2414173 October 2007 EXCERPTS FROM SANYO ECOCUTE SERVICE MANUAL Troubleshooting procedures 1 H05 Trouble in high pressure switch This trouble is confirmed after repeated 5 retnes when the refrigerant pressure has exceeded the pressure setting Checkpoints 1 Is the circulation pump lacked 2 ls any alr trapped in the connecting pipes between the heat pump unit and tank unit 3 Has water been poured into the tank unit 4 Have you forgotten to open the tank unit s shut off valves Remedial action 1 Unlock the circulation pump by referring to the trial run section in the heat pump unit s installation Instructions 2 T
27. eam orifice once the inlet pressure TBR acting on the membrane is high enough to overcome the force applied from the thermal sensor membrane system SS Mounting amp Operation The regulator needs to be placed at the evaporator inlet and the sensor element on the gas cooler outlet ensuring good thermal contact The regulator is tested to a gas cooler outlet temperature of 50 C resulting in back pressure of approx 120 bars Flow direction indication Orifice Orifice Figure 43 Danfoss TBR regulator for transcritical R744 systems For large transcritical refrigeration duties Danfoss markets an expansion valve for pressure control see Figure 44 Function Pressure control Expansion ON OFF Maximum working pressure PS 140 bar Capacity Kv 0 6 2 4 and 4 6 m h Hermetic sealed coupling Pipe connection DN 25 033 7 mm new versions Control etc See standard ICAD info ICMT 20 A Kv 0 6 ICMT 20 B Kv 2 4 CAD as AO ICMT 20 Manuel 027H0183 opening device Figure 44 Danfoss pressure control expansion valve for larger duty transcritical systems SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual Sustainable Heat and Energy Research JL JCETIA E T I A T Capillary tube membrane Sensor element 36 62 EE SHERHPA VAL YA Sstninahe Heat and Energy Research C E T I A T X for Heat Pump Applications 5 SAFE
28. ed thus reducing both flammability risks and refrigerant charge 1 3 8 Ammonia R717 Ammonia has been continuously used throughout modern refrigeration history 1 e more than 130 years despite its numerous drawbacks It is toxic and flammable in concentrations between 15 5 and 28 in air It is not compatible with copper thus requiring other materials of construction With its small molecular weight and high latent heat ammonia systems require much smaller refrigerant flow rates than those using HFCs Its thermodynamic and thermophysical properties also yield very efficient refrigeration systems Because of its acute toxicity SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 8 62 SHERHPA Sustainable d and Energy Research ws C CETIA E T I A T for Heat Pump A plications Rapport 2414173 October 2007 stringent regulations apply for ammonia systems which require close monitoring and highly skilled engineers and technicians Ammonia is often used in large stores and in process refrigeration With the development of small charge equipment ammonia may be used in smaller capacity units 2 CARBON DIOXIDE Carbon dioxide CO2 is not a new refrigerant Rather it was rediscovered in the early 90 s at the Norwegian University of Science and Technology NTNU The use of carbon dioxide as a refrigerant lasted for well over a century Its application has been progressively discontinued until it was aban
29. epends on the ambient temperature the mass of R744 charged into the system and the internal volume of the system SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 38 62 SHERHPA Sustainable Heat and Energy Research 3 CETIA E T I A T for Heat Pump A plications Rapport 2414173 October 2007 5 2 2 Operating temperatures and pressures For ambient temperatures of about 7 C typical pressures for air source heat pumps under operation are as follows e Low pressure side pressures between 25 and 50 bars and evaporating temperature between 12 C and 20 C Under lower ambient temperatures these values may be lower e High pressure side pressures between 90 and 130 bars temperatures between 90 and 130 C Refrigerant piping on the high pressure side will be therefore very hot and will cause burning Direct contact must be avoided when the unit is operating or has just been shut down 5 2 3 Material compatibility The information contained in Table 5 has been compiled from Air Liquide sources International Standards Compatibility of cylinder and valve materials with gas content Part 1 ISO 11114 1 Jul 1998 Part 2 ISO 11114 2 Mar 2001 and must be used with extreme caution No raw data such as this can cover all conditions of concentration temperature humidity impurities and aeration It is therefore recommended that this table be used to choose possible materials and then more exte
30. fe Ensure adequate air ventilation Try to stop release Prevent from entering sewers basements and workpits or any place where its accumulation can be dangerous Ventilate area Keep container below 50 C in a well ventilated place Suck back of water into the container must be prevented Do not allow backfeed into the container Use only properly specified equipment which is suitable for this product its supply pressure and temperature Contact your gas supplier if in doubt Refer to supplier s container handling instructions 8 EXPOSURE CONTROLS PERSONAL PROTECTION Ensure adequate ventilation Carbon dioxide TLVS TWA ppm 5000 Carbon dioxide TL V STEL ppm 30000 Carbon dioxide OEL UK LTEL ppm 5000 Carbon dioxide OEL UK STEL ppm 15000 Carbon dioxide MAK Germany ppm 5000 9 PHYSICAL AND CHEMICAL PROPERTIES Liquefied gas Colourless No odour warning properties 44 56 6 F8 5 s 30 57 3 bar 1 52 0 82 2000 Non flammable Gas vapour heavier than air May accumulate in confined spaces particularly at or below ground level SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 59 62 o 4 f A z v s Rapport 2414173 October 2007 RETE AIR LIQUIDE SHERHPA A D Sustainable Heat and Energy Research CA C E T I A T for Heat Pump A plications Page 3 4 SAFETY DATA
31. ge Ecocute systems from Itomic www itomic co p SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 21 62 SHERHPA SUN Sustainable Heat and Energy v C3 C E T I A T TP 2 2 for Heat Pump Ap ications TN Rapport 2414173 October 2007 Supply hot water System Flow Storage tank unit lt Boil water 90 C boiling tomic Industrial use Eco cute with CO2 refrigerant succeeded in heating water up to 90 C which was inconceivable with Freon refrigerant Even under the 10 C outdoor temperature high performance is expected damas Supply XI Enter AcCompressor B Expansion valve Circulation pump Standard type 8 500L tanks Construction by customers Absorb heat irom the air and transfer it ta tha TOUR al refrigerant i is alra to water by a Lect J Siem for air then deliver the heat to exchanger dinem to boil water SSSR RR Re RR Re eR SR RR eee SR eRe I RRR ee eR ee eee Warmed up Refrigerant is pressed on compressor The basant that loses heat is seni to the heat and becomes hotter PARTIE tfor air again Figure 13 Flow diagram of Ecocute from Itomic www itomic co jp 3 2 Green and Cool Chiller Systems Green and Cool are Swedish manufactured refrigeration and air conditioning units using R744 for high medium and low temperatures applications pi Wag wae Aie Figure 14 Atlantic chiller front view Figure 15
32. harging operation depends on the pressure in the cylinder and thus on the ambient temperature In a workshop it is recommended to use a charging station that is suitable for R744 refrigerant This station see Figure 51 and 52 will enable fine charge tuning and full cylinder exploitation Chargmz station Note Compressor 1s shut down while charzmz 744 refrigerant R744 System Metering Gas to Liquid Converter Figure 52 R744 charging system www agramkow dk SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 47 62 SHERHPA VAL Sustainable Heat and Energy Research C C E T I A T X for Heat Pump Applications Rapport 2414173 October 2007 ANNEX 1 INFORMATION ON MARKETED DOMESTIC HEAT PUMPS STIEBEL ELTRON HEAT PUMP Compact series 5 kW Powerful technology for your home The WPL 5 N sets new benchmarks for environmental responsibility anc efficiency Thanks to the variable speed compressor only as much energy as is currently required is actually consumed Using carbon dioxide as a natural refrigerant is a pioneering step for heat pump technology The small footprint anc extremely quiet operation makes this system of heat pump and cylinder universally suitable The heat pump is suitable for wall mounting anc it is connected electrically anc hycraulically to the cylincer module The module consists of an enamelled 200 litre DHW cylinder and the integr
33. heating com Measurements WxHxD 1547 x 597 x Sion mm 690 x 840 x 290 mm 180 kg bkn Power icis vM Ma 2 5 bar 100 C DHW ehaume ColsIWwe SS SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 50 62 SHERHPA A VA Sustainable Heat and Energy Research k C C E T I A T for Heat Pump Applications Rapport 2414173 October 2007 EXCERPTS FROM SANYO ECOCUTE SERVICE MANUAL 2 Outline drawings SHP C45DEN SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 51 62 Lopes GATA PITT i d anra e HS 5 Bu UMS LOS PAL IC sag A ES MCE LE aaja did TET Bue naar 4 aba axe DEO E f moy icopng CETIAT auare losis no po Jag AA N JJogug due NUE 1 supaja uun a H JSS WAH 3 i H LAS ausa JOEL eo ELEG Sustainable Heat and Energy Research for Heat Pump Applications ade opel upaja yun HUE ex A CE NE AO SHERHPA aea Ames IDR LOGO EXCERPTS FROM SANYO ECOCUTE SERVICE MANUAL suaog seuuo JO EIDEJ 104 je E useJ jnjgepe urne i JOSS op ALU Rapport 2414173 October 2007 52 62 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual SHERHPA gt VA Sustainable Heat and Energy Research k C C E T I A T a CB eee for Heat Pump Applications Rapport 2414173 October 2007 EXCERPTS FROM SANYO ECOCUTE SERVICE MANUAL Do not touch the fins of th
34. ical R744 Heat Pumps Technician s Manual 12 62 100 200 SHERHPA VAL Sustainable Heat and Energy Research C C E T I A T for Heat Pump Applications x XA ee Rapport 2414173 October 2007 2 2 Comparison of subcritical and transcritical cycles 2 2 1 Characteristics of subcritical cycles One of the most important criteria for a refrigerant is its critical point 1 e the point at which vapor can no longer be distinguished from liquid This point is indicated by values of temperature and pressure which are the critical parameters and which are characteristics of the refrigerant CIE Hi EP ELN n Ee REGIT H H JS sae L ul LH C 40 20 0 20 4b tr BU 100 120 40 iB u goro 2o mo mo me aO so aio OO mo AL EOT TA E ETAT ITEM E EE E LIE S D Pia hl REN E ee EEn ee ee E I ETE i i Dela TUN CER ES ee corel degen se His A ETTE H I 1 1 IBN a it Le be cared Ld ia bea 1 i B3 i i 5 d mus Tub ruben SES RS PS RC PE RES Bern ae L um D Vite Et i H s bi P Lem pS ye pe Y FI aH bibl adgd n LE BEE PPE pe bee E 1 d5 ae E i 4 aras rm f n mam z x T PM i rae re TE re Pees FrEE Er mi LE AT um i i 5 oF B a Er i 14 T he i r n z 1 mz T EAN EEE BAREEN m E FA 2 A a a n TIS MAT aT Li v an i x PEM nR EP ili r3 1j i i H RE UT A A T LUAM n DS MAR E E E ETE T rara T i 1
35. ithin the 30 to 65 C range in order to reduce oil carry over and R744 solubility low and high pressure relief valve with relieving set point of respectively 100 bar Pss and 163 bar PS crankcase heater special lubricant for R744 transcritical application In Japan all Ecocute manufacturers use their own proprietary transcritical compressor but only Sanyo has a complete product line that is marketed independently of their Ecocute model These rotary double stage compressors are used in some of the Coca Cola vending machines The compressor shell is at the intermediate pressure as shown by Figure 31 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 29 62 SHERHPA Sustainable Heat and Energy Research for Heat Pump Applications XA Rapport 2414173 October 2007 second compression stage BS High pressure ares 11 125 Mpa BS intermediate pressure 6 8 Mpa E Low pressure 1 3 4 Mpa First compression stage Figure 31 Sanyo double stage rotary compressor SANYO CO2 Compressor series j As of Jan 15 2004 Single Speed Model a AE AE AL AE 2 INV INV in INV INV Comp Speed 50Hz 50Hz 50Hz 50Hz Variable Variable Variable Variable Variable 60Hz 50Hz 60Hz 60Hz RaDSaus 9 Compressor Application Mass Production Base Under Development Figure 32 Sanyo compressor product line Daikin uses an in
36. ium temp Model Type of Unit Output MISTRAL MT Direct expansion on the evaporator gas cooler condenser side 30 120 kW BREEZE MT Direct expansion on the evaporator side with liquid cooled gas cooler condenser 30 120KW ATLANTIC MT Liquid chilled unit for air cooled gas cooler condenser 30 104 kW BOTHNIA Liquid chiller unit with liquid cooled gas cooler condenser 30 96 kW Freezer Unit low temp Model Type of Unit Output MISTRAL LT Direct expansion on the evaporator gas cooler condenser side 15 60kW BREEZE LT Direct expansion on the evaporator side with liquid cooled gas cooler condenser 15 60kW ATLANTIC LT Liquid chilled unit for air cooled gas cooler condenser 15 60kW ARCTIC Liquid chiller unit for pump circulation freezer with liquid cooled gas cooler condenser 15 60kW BALTIC For cascade systems Direct expansion on evaporator side Secondary fluid on 15 60kW condensorside is connected to the evaporator side on glycol chiller MT Chiller unit Freezer unit Model Type of Unit Output Chiller Output Freezer CRYSTAL CH Liquid chilled unit with a combined freezer unit for direct expansion 60 90kW 10 30kW CRYSTAL DX combined chiller unit and freezer unit for direct expansion on evaporator 60 90kW 10 30KW side and gas cooler side 070517 GREEN amp COOL Handelsv gen 15B SE 97345 Lule SWEDEN Tel 46 920 203031 Fax 46 920 203035 E mail co2 amp greenandcoolco2 com SHERPHA PROJECT Transcritical R744 Heat Pumps Technici
37. l extinguish an open flame Breathing air that contains more than 10 R744 can be life threatening This corresponds to spreading uniformly about 24 kg of R744 in a workshop that is 4 m wide 10 m long and 3 m in height one ppm is equivalent to one cubic centimeter per cubic meter SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 9 62 SHERHPA VAL Sustainable Heat and Energy Research C C E T I A T X for Heat Pump Applications Gaseous R744 is 1 5 times heavier as air Therefore when released to the air it will concentrate at low elevations R744 will form dry ice at 78 4 C One kg of dry ice has the cooling capacity of 2 kg of ordinary ice Gaseous or liquid carbon dioxide stored under pressure will form dry ice through an auto refrigeration process if rapidly depressurized Figures 2 and 3 show the thermodynamic properties of R744 Compared to other fluids traditionally used as refrigerants its critical point at 31 C is very low and its critical pressure at about 74 bars is high These differences have as shall be discussed important consequences on heat pumping cycles using R744 e gt o o oe ec ee es oe Critical 9 959 55 5 9 9 9 9 ST M Xm ve rr cn c Solid Liquid Liquid vapour 56 6 Deg C Solid Vapour 78 4 Deg C 9 9 RV 4 8 A ONS 0 489 9 K N 827 AN 94 8 9 0 Det PT
38. m pressure is less than around 6 bar because of expansion see Section 6 1 1 Before charging liquid R744 into the system on the high pressure side it is therefore necessary to increase the system pressure to a level of about 6 bar using gaseous R744 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 45 62 ee EE ee M Ee Owe SHERHPA VA e m LL Sustainable Heat and Energy Research C E T I A T for Heat Pump Applications Rapport 2414173 October 2007 Once this value is reached recharging may proceed with liquid R744 The correct system charge must be known from the Service Manual Do not attempt to charge an R744 system when the amount of refrigerant charge is unknown This may lead to system overcharge and to high pressure increase 6 1 3 R744 containers and recharge system Refrigerant R744 is available in pressurized cylinders with contents ranging from about 3 to 35 kg R744 is produced by chemical companies such as Linde Gas Air Liquide and Praxair Cylinders are made of steel or aluminum with a service pressure between 125 and 200 bars Linde Gas available cylinders are listed in Table 6 The first column indicates the cylinder reference and the second column the R744 net content The equivalent volume in gaseous form at 1 atm and ambient conditions is shown in the third column Assuming a workshop with a width of 4 m a length of 10 m and a height of 3 m the last column
39. medial action Tum off the power close the shut off valves of the tank unit and change aver the connecting pipes SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 54 62 SHERHPA ACETIAT 2 ae Sustainable Heat and Energy Research for Heat Pump Applications XA Rapport 2414173 October 2007 EXCERPTS FROM SANYO ECOCUTE SERVICE MANUAL Before replacing the heat pump unit Be absolutely sure to check the fol owing points before diagnosing the trouble as originating in the refrigerant circuit 1 Datheoutdoor temperature and current levels stand in their proper relationship See page 25 If the levels are within the reference values there is no trouble in the closed circuits 2 ls power supplied ta the heat pump unit 230 between black and wj 3 lsthere any trouble with the thermistors Check the error history Se 4 Is the fan running b Are the electrical wires between the tank unit and heat pump unit plugged into the terminal board securely Do not install the heat pump unit Do not damage or rework the power indoors cord and do not use a damaged or The oxygen in the air may become NEC bundled cord deficient if the refrigerant should leak Prohibit Be absolutely sure to ground the unit Otherwise you may receive an electric mn Do not touch the heat pump pipes shock ifthe unit should fail or power UNJ You may burn yourself should leak Do not install the unit nea
40. mpression it reaches a temperature of 120 C It is then cooled in a gas cooler expanded and 1s evaporated to complete the cycle The main features of the transcritical cycle are then as follows e The cycle operates at much high pressures than the traditional cycle typically between 30 bars evaporator side and 130 bars gas cooler side SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 14 62 ME SHERHPA j A Sustainable Heat and Energy Research for Heat Pump A M bm LA pplications GOCETIAT Rapport 2414173 October 2007 e The high pressure is no longer fixed by the cooling fluid temperature or flow rate therefore there is a need to control this parameter e The high pressure refrigerant is not condensed it is cooled as a supercritical fluid e n most cases the refrigerant flow rate is not fixed based on the value of superheat at compressor suction e The more refrigerant charge there is in the high pressure side the higher the pressure will be 1 000 z z F Pe 4 E r rt ae J Pa 4 P p ch E od E t p t v E rote A j AG 7 8 di i i Original Mollier with Copyright 1999 b e f 4 E E 3 p z ChemicaLogic Corporation E d CPE www chemicalogic com TL RS LR Cycle additions CETIAT Mi 4 4 F y P 4 2 E i LI D e o 23 o o o oO 100 VAAT a
41. n 2 Compression 10 er ES A Ls 200 100 Figure 6 A transcritical cycle using R744 2 3 Optimum pressure with the transcritical cycle It was seen that for the subcritical cycle the condenser pressure was fixed by the condensing temperature which in turn is a function of the condenser size and the cooling fluid flow rate and temperature For the transcritical cycle the gas cooler pressure is not a function of the R744 temperature because there is no unique relationship between temperature and pressure above the critical point This means that the system can operate at different values of high pressure which can be set by the control scheme SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 15 62 SHERHPA Sustainable di and Energy Research A C5 CETIA E T I A T for Heat Pump Applications Rapport 2414173 October 2007 In such a system the pressure is therefore fixed by a control device so that the cycle operates under optimum conditions yielding the best energy efficiency Energy efficiency is defined as the amount of useful energy divided by the amount of input energy Hence in heating mode the energy efficiency or Coefficient of Performance is defined as HeatingDuty kW COP Electric Power kW Pressure T constant d We Pigi Hish Pressure Enthalpy Figure 7a Duty vs Electric power Figure 7b
42. nsive investigation and testing 1s carried out under the specific conditions of use The collected data mainly concern high pressure applications at ambient temperature and the safety aspect of material compatibility rather than the quality aspect SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 39 62 SHERHPA UN Sustainable Heat and Energv Research Se C E T I A T 21 J c AH for Heat Pump Applications Rapport 2414173 October 2007 Table 5 R744 compatibility with materials A Material Compatibility Satisfactor oatisfactory but risk of corrosion in Ferritic Steels e g Carbon steels presence of CO and or moisture Cold brittleness Stainless Steel Satisfactor Non recommended significant swelling and Nitrile rubber NBR significant loss of mass by extraction or Non recommended significant swelling and Chloroprene CR significant loss of mass by extraction or Non recommended significant swelling and Chlorofluorocarbons FKM VITONTM significant loss of mass by extraction or chemical reaction Acceptable but important swelling and Ethylene Propylene EPDM significant loss of mass by extraction or chemical reaction Lubricants Fluorocarbon based lubricant Satisfactor 5 2 4 Water and R744 Figure 45 from Danfoss technical literature shows what the combination of water and R744 leads to SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Man
43. o avoid water contamination of oil e Avoid letting the circuit open to the air during servicing when not required always remove caps or bolts just before welding tightening e Change filter dryer cartridge upon servicing 6 SERVICING AND MAINTENANCE ASPECTS This Section attempts to explain the fundamentals of R744 behavior and its consequences on the Servicing and Maintenance aspects of R744 heat pumps R744 heat pumps must be treated as hot water heaters In particular the refrigerant circuit 1s tuned in the factory and should therefore not be tampered with except by fully authorized personnel Note that Annex 1 contains information material from an Ecocute manufacturer Consult this Annex for further advice on how to handle such heat pumps 6 1 1 Evacuating R744 the expansion process Upon expansion refrigerants tend to cool R744 possesses a high triple point around 56 C and 5 2 bars Therefore care must be taken to avoid sudden pressure release that would bring it to solid state or any expansion process which could lead to such a state Figure 50 illustrates the R744 expansion processes from different pressure levels e Expanding vapor from point C 35 bars to the triple point pressure will result first in the partial vaporization of R744 and will then lead to gaseous state e Expanding vapor from point B 50 bars will lead to a 5 of the refrigerant in solid state dry ice at the triple point pressure e Ex
44. ooler exit temperature of 45 C requires a high pressure of about 125 bars This equation is valid for temperatures between about 38 and 53 C 2 4 Transcritical cycle vs Traditional cycle Table 2 summarizes the main design differences between the subcritical traditional cycle and the R744 transcritical cycle As mentioned in the previous sections the main differences lie in the pressure levels both during operation and at standstill and the methods implemented to ensure the control of high pressure and refrigerant flow rate Table 2 Main differences between transcritical R744 cycle and subcritical cycle Cycle parameters Subcritical Transcritical CO2 High pressure cooling heat Condenser Vapor condenses at Gas cooler CO2 undergoes rejection device constant temperature large temperature change Discharge pressure HFCs from 10 to 40 bars from 90 to 130 bars HFCs from 2 to 9 bars hw 25 to 50 bars PEU tee Usually less than 95 C Up to 140C temperature By superheat set point or fixed flow Usually used to control high Expansion device controls expansion device device pressure of CO2 of CO2 High pressure controls pressure controls Not controlled Pressure is set by excluding safety shut down condensation temperature Required Up to 130 bars controls usually 40 bars max Gas supercritical above 31 C ambient vapor liquid mixture below 31 C Can become solid
45. panding liquid from any pressure e g point A at 20 bars will lead to a substantial amount of R744 dry ice in the equipment This also occurs when the expansion process starts from other higher pressures e g higher saturation temperatures SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 43 62 SHERHPA VA Sustainable Heat and Energy Research C C E T I A T X for Heat Pump Applications Rapport 2414173 October 2007 Pressure psi bar 31 C 87 9 F 1450 100 c ti Supercritical OOOO DO OTTII pe E Vapour Liquid 50 bar 725 psi Vapour 20 bar 290 psi Solid Liquid Liquid vapour 0 solid CO at 148 10 78 solid CO at the triple point Solid the triple point 56 6 C 69 9 F 5 2 bar a 75 1 psi a cali N 5 solid CO at Solid Vapour the triple point 78 4 C 109 1 F vapour 14 5 1 Enthalpy J Figure 50 R744 expansion processes As a rule of thumb the expansion of liquid R744 from any pressure level and the expansion of gaseous R744 from a pressure higher than 35 bars will lead to the formation of dry ice if the final pressure is lower than about 5 2 bars This specific behavior should be borne in mind for example when discharging R744 from systems As of year 2007 there 1s no obligation to recover R744 from refrigeration heat pump systems Hence R744 can be discharged to the atmosphere In the event of a R744 release from
46. r a source of gas or objects which may ignite or catch fire Do not touch the fins of the heat pump There is a risk of combustion or a fire unit and do not poke your hands or any bar shaped objects into the air Do not charge the refrigerant in the ohibiteg intake and outlet heat pump unit You may injure yourself The unitis not constructed to be amenabie to refrigerant charging Be absolutely sure to have a qualified Do not attempt to disassemble and contractor do the water supply and repair the unit yourself leave these electrical work jobs to a qualified repair technician Otherwise accidents or malfunctioning There is a risk of combustion and you is may result nu iba yourself as a result of an SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 55 62 SHERHPA Sustainable Heat and Energy Research k oC E T I A T for Heat Pump Applications wf 2 ae Rapport 2414173 October 2007 ANNEX 2 CHILLERS COOL green refrigeration systems BREEZE 390MT MM EEUU Air Conditioning Unit high temp Model Type of Unit Output MISTRAL HT Direct expansion on the evaporator gas cooler condenser side 40 200 kW BREEZE HT Direct expansion on the evaporator side with liquid cooled gas cooler condenser 40 200kW ATLANTIC HT Liquid chilled unit for air cooled gas cooler condenser 40 200 kW PACIFIC Liquid chiller unit for air cooled gas cooler condenser 40 200 kW Chiller Unit med
47. re limit 100 increase in breathing rate 300 increase in breathing rate headache and sweating may begin after about an hour 5 Com this will tolerated by most persons but it is physical burdening Short time exposure limit Headache after 10 or 15 minutes Dizziness buzzing in the ears blood pressure increase 8 10 high pulse rate excitation and nausea After a few minutes cramps similar to epileptic fits loss of consciousness and shock i e 10 18 a sharp drop in blood pressure The victims recover very quickly in fresh air 18 20 Symptoms similar those of a stroke Note that with a relative density of 1 53 R744 is heavier than air thus it tends to concentrate near the ground level when spilled SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 37 62 SHERHPA Sustainable d and Energy Research ws C CETIA E T I A T for Heat Pump A plications Rapport 2414173 October 2007 Air source heat pumps are always installed outdoors that is where they pick up heat Since connecting pipework between the heat pump and the hydraulic system contains only water and because of the double wall separating water and R744 in the water heater there is no possibility of leakage of R744 in the water circuit A water source heat pump can be installed indoors Installation should be carried out correctly to avoid accumulation of R744 in specific locations should a leak occur e Ventilation must be p
48. reen and ool hiller S VStCINS iustos rra eve quadr cesse ee Si ocu ME PRU E 22 3 3 Vending machines and bottle coolers ss 23 4 COMPONENTS FOR R744 HEAT PUMPS eee 25 CODES S OS estate oos en oe todo aitensit rode ce Eod ep SE 25 Bh ie eV 1 O1 OF AWM RP 31 Bi As OO nue sdqnsanessonesezatucceenenseeetdqpeoseudoraee 32 4 4 Expansion devices and controls 34 5 SAFETY GUIDELINES WHEN USING R744 IN HEAT PUMPS 37 SRA Fec on Healtli onore vs ereo ru E N E E eoru im Lonses dU 37 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 2 62 SHERHPA 7 Sustainable Heat and Energy Research C C E T I A T for Heat Pump Applications 32 RA m heat DUMAS REO 38 5 2 1 Pressure at standstill seie a E nanas ce 38 5 2 2 Operating temperatures and pressures 39 5 2 3 Material compatibility 2a oio ete etwa tu bau eto as Ra ERR DEI g e e PR PAUSE 39 SF VY Ne ANG Fo ET S 40 6 SERVICING AND MAINTENANCE ASPECTS 7 eere eene eene 43 6 1 1 Evacuating R744 the expansion process Us 43 6 1 2 Recharging R744 heat pumps ss 44 6 1 3 R744 containers and recharge system ss 46 ANNEX 1 INFORMATION ON MARKETED DOMESTIC HEAT PUMPS 48 ANNE 2 CALLER m E 56 ANNEX 3 SAFETY DATA SHEET sccscsassacsecesiasanedssansaessaasensasagesadesdsaenssesnasaeaeaaaensazaaasacss 58 SELEC TED REFERENCES erse 62 SHERP
49. rgy efficiency than that of R134a As a by product of the oil industry isobutane 1s cheaper than R 134a The use of isobutane requires minimal design changes such as the relocation of potential ignition sources outside of the refrigerated compartment Isobutane is used worldwide except in the USA where legal liability fears over the long term inhibit manufacturers to market hydrocarbon systems 1 3 2 Propane R290 With a boiling point of 42 C propane is an excellent alternative to R22 as it requires similar working pressures An added advantage is that except for added safety measures because if its flammability virtually no design change is required in systems when switching from R22 to propane The combination of its good thermodynamic and thermophysical properties yields systems that are at least as energy efficient as those working with R22 The use of propane is increasing in countries where regulations allow it When used on the high temperature side of a cascade refrigeration system propane provides cooling to condense a lower temperature fluid Hence propane can be combined with carbon dioxide in cascade systems that are used in large food processing or refrigeration plants with both high energy efficiency and minimum environmental impact Propane can also be used for heat pump applications particularly in systems using secondary fluids water or glycols to absorb and reject heat In this case a compact sealed unit can be design
50. rovided Avoid working with R744 where it can be collect in low or confined areas e Do not remain near the heat pump in the event of a large carbon dioxide release Before returning to the premises make sure that the R744 concentration is low enough The R744 concentration can be analyzed with specific sensors e R744 containers must stand upright when gas is being withdrawn Cold R744 can form a very thick mist with moist air e Persons who succumb to R744 poisoning must be taken into the open air quickly Artificial respiration should be administered if the victims stop breathing 5 2 R744 in heat pumps 5 2 1 Pressure at standstill Because of their high value of critical temperature the pressure at standstill 1 e when the system is shut down for conventional refrigerants is a function of ambient temperature assuming the system temperature has reached that value Even under severe ambient temperatures most HFC HCFC refrigerants systems exhibit pressures lower than 40 bars at standstill For R744 the standstill pressure evolves as follows e For ambient temperatures under 31 C the pressure is equal to that above the vapor phase i e the standstill pressure is equal to the saturation pressure of R744 At a temperature of 31 C this pressure reaches about 75 bars e For ambient temperatures above 31 C all the R744 contained in the system is under supercritical conditions Thus the standstill pressure is above 75 bars but d
51. t the special R744 properties Figure 35 shows such an evaporator from Daikin The all aluminum evaporators are used for mobile air conditioning but their use is envisaged in stationary equipment for cost considerations 4 3 Gas coolers The gas cooler is the R744 to water heat exchanger that heats up water in a heat pump Most gas cooler designs use a double wall separation between R744 and water In the event of a leak R744 will thus never mix with water Some sample gas coolers are shown in Figures 36 to 39 Plate heat exchangers are not used due to pressure limitations on their design as of 2007 The Sanyo gas cooler uses superimposed wounded coils with alternate circulation of water and R744 Water flows through flattened tubes while R744 flows through flat tubes with several ports Stiebel Eltron Figure 37 use a layout that is similar to that used by Denso Figure 38 In these designs R744 flow through small diameter copper tubing that is welded to copper plates though which water flows The Denso design uses extra fins baffles between the water plates to increase surface area and turbulence The Daikin design uses regular water tubing around which is soldered to small helically wounded copper tubing see Figure 39 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 32 62 SHERHPA VA Sustainable Heat and Energy Research C C E T I A T XM Dr A for Heat Pump Applications Rapport 2414173 Octo
52. te refrigerant charge could thus lead to improper heat pump operation and or equipment damage This explains why most residential heat pumps are only serviced in the manufacturer workshop or at an authorized service station Thus any attempt to recharge R744 heat pumps should not be made unless it is authorized by the manufacturer Recharging a R744 system can only by carried out if full and explicit instructions are provided by the heat pump manufacturer Annex 1 which shows excerpts from an Ecocute Service Manual issues important warnings against attempts to recharge the unit Systems using R744 must be thoroughly evacuated like conventional refrigeration systems Before any servicing make sure that all the following is available to carry out refrigerant recharging e Instructions from the manufacturer including required information e g the total amount of refrigerant for recharge e Components required e g filter driers for R744 and suitable for the required design operating pressures should be used e Appropriate recharging station if specified by manufacturer Recharging R744 systems like conventional systems is not readily possible With HFC refrigerants and other systems it is common practice to recharge liquid via the liquid line upon completion of the evacuation 1 e when the plant is still under vacuum This is not possible with an R744 system because dry ice would form internally at the charging point when the syste
53. temperature C 30 Vapour pressure 20 C 57 3 bar Relative density gas air 1 A kr Relative density liquid water 1 0 82 Solubility in water mg l 2000 Flammability range vol in air Other data AIR LIQUIDE SA France Non flammable Gas vapour heavier than air May accumulate in confined spaces particularly at or below ground level SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 58 62 a AIR LIQUIDE SHERHPA Sustainable Heat and Energy Research for Heat Pump A GOCETIAT p lications Page 2 4 Revised edition no 1 Date 15 7 2005 SAFETY DATA SHEET Carbon dioxide Special protective equipment for fire fighters 6 ACCIDENTAL RELEASE MEASURES Personal precautions Environmental precautions Clean up methods 7 HANDLING AND STORAGE Storage Handling Personal protection Occupational Exposure Limits Physical state at 20 C Colour Odo u r Molecular weight Melting point C Boiling point C Critical temperature C Vapour pressure 20 C Relative density gas air 1 Relative density liquid water 1 Solubility in water mg l Flammability range vol in air Other data AIR LIQUIDE SA France 5 FIRE FIGHTING MEASURES continued In confined space use self contained breathing apparatus Evacuate area Wear self contained breathing apparatus when entering area unless atmosphere is proved to be sa
54. ter decompression etc These issues hinder the fast development of a component chain In Japan the mostly available components for transcritical cycles are those used in the Ecocute systems viz air coils evaporators compressors electronic expansion valves EEVs and water to R744 heat exchangers gas coolers In Europe few manufacturers have an offer for R744 components except Danfoss which mainly markets compressors and valves In this section we will examine the marketed items or to be marketed as claimed by component manufacturers and describe their respective technologies 4 1 Compressors Bock markets semi hermetic electrical driven compressors for transcritical R744 cycles aiming at industrial and commercial refrigeration or air conditioning applications The two cylinder fixed displacement compressors have an integrated gas cooled electric motor 4 pole version 1 500 rpm with swept volumes ranging from 90 to 190 cc which yields displacement volumes from 7 70 m h to 20 m h The HGX2 and HAX2 compressor series can handle variable rotational speed with a maximal 1800 rpm They are equipped with HP and LP safety valves and use synthetic oil Their overall weight is about 160 kg Figure 21 Bock Series HGX2 Figure 22 Bock Series RKX26 31 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 25 62 Le PAN SHERHPA ES p A Sustainable Heat and Energy Research won C CETIA E T I A
55. the refrigerant critical temperature be above the temperature of the medium where heat is rejected Condensing refrigerant vapor then yields a condensing l The temperature above which liquid cannot exist SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 4 62 SHERHPA Sustainable Heat and Energy Research AX C5 CETIA E T I A T for Heat Pump Applications Rapport 2414173 October 2007 pressure that is below the refrigerant critical pressure In this cycle condensing pressure and temperature are linked by a unique relationship that depends on the nature of the refrigerant In a transcritical cycle the liquefaction process or gas cooling occurs above the critical pressure while evaporation occurs at a pressure below the critical pressure With a few exceptions all cycles use working fluids below their critical pressure 1 2 A brief history of refrigerants Briefly stated the history of refrigerants can be divided into three periods A first era which started roughly around 1830 and lasted up to about 1930 where any available substance that produced refrigeration was used This era was qualified as the whatever worked period since the main selection criterion for a refrigerant was its ability to be used in practical systems regardless of its toxicity flammability and compatibility with the environment Although most of them were toxic and or flammable solvents and volatile fluids were
56. then used With the development of comfort air conditioning and refrigeration to a very large scale and to the public at large new and safer refrigerants became necessary A second era dating from 1931 to about 1994 marked by the development and promotion of the CFCs Chloro Fluro Carbon refrugerants and HCFCs Hydoro Chloro Fluoro Carbon refrigerant as aerosol propellants blowing agents and refrigerants These refrigerants where named the miracle substances because they met all the criteria required to be used at the time stability safety efficiency etc However these substances mostly chlorinated The ozone hole in the Southern compounds proved to be too stable and their long term Hemisphere Nasa 2006 effects were totally ignored until their accumulation in the stratosphere resulted in the partial destruction of the ozone layer In order to restore the ozone layer a scheduled worldwide phase out of the CFCs and HCFCs was agreed upon by the Montreal Protocol and its subsequent amendments As an example HCFC refrigerant R 22 can no longer be used in new equipment in Europe since 2004 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 5 62 SHERHPA Sustainable d and Energy Research ms CETIA E T I A T for Heat Pump Applications Rapport 2414173 October 2007 A third era dating from 1994 during which HFCs Hydro Fluoro Carbon refrigerants have been massively introduce
57. ting 3 1 The Ecocute system for tap water and heating EcoCute is a brand name that applies to a system which is made by 6 Japanese manufacturers Denso Daikin Sanyo Matsushita Electric Industrial Hitachi Appliances Mitsubishi Electric and Sanden and marketed under about 14 names The brand name is derived from the Japanese word kyuto which means hot water The development of the Ecocute was motivated by the need to i a E Fk rudi mij 1 FRI f i JL i LN 4 La Rte i HE CA ILI ES TN SF HZZDLDN L rin produce hot water at a cheaper cost while operating at reduced electricity tariffs Sanyo is one of the main manufacturers releasing an Ecocute unit that Figure 8 Sanyo Ecocute produces hot water and heating water Figure 8 l www sanyoaircon com shows the heat pump and associated water tank It is noteworthy the heat pump looks just like any other traditional air outdoor unit or minichiller on the market This outdoor unit has neither an integrated water tank nor a water pump In addition to the electrical connections only the water connections are required The water distribution system inside the house remains the same as with other heating systems Figure 9 shows the flow diagram of such a unit The water circulates inside the tank and is heated by the heat pump unit as required Water is withdrawn from the tank to feed the radiators or space heating system and then returns to the tank
58. tion if needed In order to avoid water pipe freezing in very cold climate areas a manufacturers has marketed an Ecocute version with a water to R744 heat exchanger the gas cooler located just below the water tank This tank is then installed indoors while the heat pump is installed outdoors Since only hot R744 circulates in the pipes between the heat pump and the water tank there is no risk of water freezing In Europe a 5 kW heat pump with features similar to that of the Ecocute unit 1s marketed by Stiebel Eltron Annex 1 shows a brochure relevant to the Compact series 5 kW from this manufacturer and from CTC a Sweden based manufacturer which proposes similar heat pumps Annex also shows excerpts of Instruction Manuals from Ecocute manufacturers Residential Ecocute units yield heating duties of the order of 4 5 kW Japanese manufacturers claim to have produced a million Ecocute units up to year 2007 cumulated Some larger capacity R744 heat pumps are under development targeting the commercial market The simplest models use two small domestic Ecocute units in series for water and space heating see example in Figure 11 Some Japanese manufacturers also market larger units aiming industrial and large residential applications hotels hospitals cafeterias etc Figure 12 shows an Itomic system installed on a building roof It uses a large water capacity 6 times 500 I Figure 13 shows the water and R744 circuits Figure 12 Lar
59. tly indirect system Refrigerant R744 Refrigeration output KW 26 52 78 104 Compressor quantity 1 2 3 4 Secondary fluid Propylene glycol 37 Temp of Secondary fluid C In Out 4 8 4 8 4 8 4 8 Evaporation temperature C 12 12 12 12 Low temperature LT TISLT 2301T 3451T 4601T Chiller units Freezer unit Partly indirect system Refrigerant R744 Refrigeration output KW 15 30 45 60 Compressor quantity 1 2 3 4 Secondary fluid R744 Temp of Secondary fluid C 30 30 30 30 Evaporation temperature C 35 35 35 35 Discharge temperature from gas cooler 30 C Refrigeration outputs shown in the table are based on design temperatures Some outputs are preliminary and should be determined in actual operational conditions as ambient temperature and water temperature will influence the output values GREEN amp COOL Handelsv gen 15B SE 97345 Lule SWEDEN Tel 46 920 2023031 Fax 46 920 203035 E mail co2 greenandcoolco2 com 070517 SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 57 62 SHERHPA Sustainable Heat and Energy Research for Heat Pump Applications GOCETIAT Rapport 2414173 October 2007 ANNEX 3 SAFETY DATA SHEET Page 2 4 Revised edition no 1 Date 15 7 2005 Supersedes 0 0 0 AL018A Special protective equipment for fire In confined space use self contained breathing apparatus fighters SAFETY DATA SHEET AIR LIQUIDE Carbon dio
60. ual 40 62 SHERHPA x m Sustainable Heat and Energy Research AC E T I A T for Heat Pump Applications x XA D Cree po Wwateris resent in CO systems water reacts with CO E este ee E p z euet DOUDD IE IL SCO CRCRE TT Wd EA ee D AR MR DA UAM ns AR nanas ee Mm T AM AUAM AARAU CUL MEC dd d UU ULLA AERAR a R R R S PRE E S EES ES AEREE 40 depending on the water content ur In a first step R744 and water combine to yield carbonic acid with a mild effect However this acid further combines with R744 to give a hydronium ion which has the effect of an activated acid and reacts with construction materials such as steel The acid attack shown in Figure 46 is a form of R744 corrosion that occurs in flowing environments and occurs Figure 46 Pipe corrosion in flowing environment where a protective iron carbonate octane nmt edu waterquality corrosion CO2 htm coating is worn away in areas SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 41 62 SHERHPA UN Sustainable Heat and Energy Research C C E T I A T for Heat Pump Applications e NM Rapport 2414173 October 2007 CO gas hydrate CO H O With very high concentration of water in R744 systems the R744 gas hydrate can be formed The R744 gas hydrate see Figure 47 looks like ice but exists also at higher temperat
61. ures than 0 C The CO2 gas hydrate can create problem e g plugging filters and pipes Figure 47 R744 gas hydrates www danfoss com Water can also enter the system via the lubricant oil With synthetic mineral oil such as Poly Alpha Olefin lubricant oil oxygen generated by corrosion for example reacts and yields water and a strong organic acid This acid in turn reacts on construction materials Figure 48 Effect of oxygen on mineral oil www danfoss com With ester oil free water combines to form an alcohol and a relatively weak acid see Figure 48 However when these reaction products are carried around in the refrigeration system high temperatures will be encountered with an amplification of the acidic effects Figure 49 Effect of water on ester oil www danfoss com SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 42 62 SHERHPA TK Sustainable Heat and Energy Research C C E T I A T for Heat Pump A plications Water can enter the system mainly because of the following reasons e Incomplete water removal during installation commissioning e Water contaminated lubricant charged into the system e Water contaminated CO2 charged into the system It is therefore very important to avoid water contamination through good service practices e Thoroughly vacuum systems same procedure and duration as HCFC HFC refrigerants e Avoid letting oil cans open always put the cap back t
62. urn off the power and disconnect the pipes Thoroughly purge the air from the pipes and then re connect the pipes 3 Pour water into the tank unit id Refer to page 11 in the tank units Technical Manual and open the three valves 2 H23 Boil up trouble The boil up temperature is at variance from the target value Checkpoints When the bail up temperature is too high this kind of trouble occurs when it is not possible to provide the circulation flow required for bail up 1 ls the water failing to circulate between the tank unit and heat pump unit i2 ls a pipe whose diameter does not satisty the rating which Is smaller than the rating being used When the boil up temperature ts too low this kind of trouble occurs when the circulation flow is too high or heat quantity is insufficient 3 lsapipe whose diameter does not satisfy the rating which is larger than the rating being used 4 Have the pipes been insulated properly Remedial action 1 Turn off the power and replace the circulation pump GWU se pipes with the rated diameter and length in accordance with the installation instructions d Insulate the pipes and areas where the units are connected 3 H27 Incorrect water circuit piping connection The pipes between the heat pump unit and tank unit are crossed and connected in reverse Checkpoint sthe circulation pump side of the tank unit connected to the water side B of the heat pump unit Re
63. ustainable Heat and Energy Research i R C E T I A T X Rapport 2414173 October 2007 The TCS Dorin product line features single stage compressors that operate under transcritical conditions and are suitable for e Refrigerated transport e Commercial refrigeration e Hot water production and heating e Chiller and HVAC systems The TCS are also proposed in tandem arrangement T TCS line Figure 27 Dorin compressor Figure 28 shows the main features of the TCS Dorin compressors Figure 29 shows a drawing of a sample compressor with dimensions transcritical single stage swept volume discharge mah f NPT TCS340 4 D transcritical single stage LRA A nominal motor 380V 50hz 380V 50hz power kW TCS3404 D TCS350 4 D TCS362 4 D 215 1 TCS362 D TCS373D Figure 29 Dorin TCS product line TCS340 eor ing OPUSUL unt QUE SELL Ip eyeloo wig HERO IGU Deuce RIO GIO E SURES Joni SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 28 62 o aS E for Heat Pump Rapport 2414173 October 2007 SHERHPA VA Sustainable Heat and Energy Research CA C E T I A T amp A plications 395 GIL DRAIN SUCTION Figure 30 Compressor dimensions Standard compressors from Dorin are PED certified and equipped with electric motors with thermistor protection oil pump and oil cooler the oil temperature 1s controlled so as to remain w
64. verter swing type compressor with a high pressure shell Figures 33 and 34 show details of the Daikin compressor construction SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 30 62 SHERHPA VA Sustainable Heat and Energy Research C C E T I A T X for Heat Pump Applications Figure 33 Daikin compressor Figure 34 View of Daikin swing compressor 4 2 Evaporators Heat pump evaporator technologies use either finned coils plate and tube air source or plate heat exchangers and shell and tube for liquids p a7 t ni rn Figure 35 Daikin air to refrigerant evaporator with fan on Ecocute chassis SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 31 62 o E SHERHPA Sustainable d and Energy Research wn gt CETIA E T I A T for Heat Pump A plications Rapport 2414173 October 2007 Refrigerant to liquid plate heat exchangers are not available for pressures higher than about 40 bars except for very costly customized industrial applications Plate heat exchangers are therefore not used in transcritical cycle because of the pressure constraints as of 2007 The Ecocute units use finned tube air to refrigerant evaporators that use copper tubes and aluminum fins Basically these evaporators are not different from heat exchangers using HFC refrigerants However they are equipped with thicker tubes and specific circuitry that takes into accoun
65. w car models to a value of 150 In September 2007 the German automakers association VDK selected carbon dioxide as its preferred R134a alternative for automobile air conditioning 1 3 Natural refrigerants applications Some European countries such as Denmark have already locally enforced rules to limit the use of HFCs This trend is spreading to other European countries With increasing environmental awareness it is therefore expected that many refrigeration applications presently using HFCs will require other refrigerants 2 This date marks the introduction of refrigerant R134a in automobile air conditioning SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 6 62 o C LN SHERHPA VA SS v om Sasteinabin Heat and Energy Research C E T I A T XD D A for Heat Pump Applications Rapport 2414173 October 2007 Table 1 Environmental impacts and properties of some refrigerants Boiling Critical Critical 1 GWP MA mE pressure ODP Flam bar 100 yrs ar Lm es ane los mmo mmea o m 408 962 498 0055 1500 mineral mo Pure HFCs m 821 256 482 o 12000 eser no R32 16 784 583 o 650 ester yes RIS 435 680 363 o 2500 eser no Cmm 265 oi 307 o 19 eser no Rista 250 1135 452 o 140 eser yes HFC mixtures Raos sos ms ws o 1900 eser no Raosa 464 nvi 374
66. xide 5 FIRE FIGHTING MEASURES continued 6 ACCIDENTAL RELEASE MEASURES Evacuate area Wear self contained breathing apparatus when entering area unless atmosphere is proved to be safe Ensure adequate air ventilation Try to stop release Prevent from entering sewers basements and workpits or any place where its accumulation can be dangerous Ventilate area Personal precautions Environmental precautions Clean up methods 7 HANDLING AND STORAGE Keep container below 50 C in a well ventilated place Suck back of water into the container must be prevented Do not allow backfeed into the container Use only properly specified equipment which is suitable for this product its supply pressure and temperature Contact your gas supplier if in doubt Refer to supplier s container handling instructions 8 EXPOSURE CONTROLS PERSONAL PROTECTION Ensure adequate ventilation Carbon dioxide TL VO TWA ppm 5000 Carbon dioxide TL VO STEL ppm 30000 Carbon dioxide OEL UK LTEL ppm 5000 Carbon dioxide OEL UK STEL ppm 15000 Carbon dioxide MAK Germany ppm 5000 9 PHYSICAL AND CHEMICAL PROPERTIES Storage Handling Personal protection Occupational Exposure Limits Physical state at 20 C Liquefied gas Colour Colourless Odo u r No odour warning properties Molecular weight 44 Melting point C 56 6 Boiling point C 78 5 s Critical
67. y should be carried out Details given in this document are believed to be correct at the time of going to press Whilst proper care has been taken in the preparation of this document no liability for injury or damage resulting from its use can be accepted Recommended uses and restrictions This SDS is for information purposes only and is subject to change without notice Prior to purchase of products please contact your local AIR LIQUIDE office for a complete SDS with Manufacturer s name and emergency phone number End of document AIR LIQUIDE SA France SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 61 62 SHERHPA VA Sustainable Heat and Energy Research C C E T I A T for Heat Pump Applications Rapport 2414173 October 2007 SELECTED REFERENCES Further documents and information can be found from the following Internet web sites www sherhpa com WWW r744 com www danfoss com WWW itomic co p WWW sanyoaircon com www heatpumpcentre org www agramkow dk www greenandcool se http www ctc heating com SHERPHA PROJECT Transcritical R744 Heat Pumps Technician s Manual 62 62

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