module 1 - introduction to alternative refrigerants

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Introduction

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Aim

Aim of this Guide

You are about to start a trial of this e-learning module. Whencompleted please go to the TEST page to take the sampleassessments and then follow the link to complete the EvaluationSurvey (will open in a new SurveyMonkey window).AimThe aim of this guide is to provide an introduction to the different alternatives to high globalwarming potential (GWP) hydro fluoro carbon (HFC) refrigerants and to compare their properties,performance, safety issues, environmental impact and ease of use. These refrigerants are used innew, specially designed systems they are rarely suitable to replace refrigerants in existingsystems.The main alternatives have low to zero GWP, but it is important that a refrigerant is not selectedon the basis of low GWP alone; other characteristics should be taken into account such as: Operating pressures; Performance capacity and efficiency; Material compatibility, including compressor lubricant; Safety, including flammability and toxicity; Temperature glide; Ease of use and skill level of design engineers and technicians who install, service andmaintenance.The document provides useful reference material for anyone working in the refrigeration, airconditioning and heat pump (RACHP) industry. It assumes you already have knowledge ofRACHP systems which use HFC refrigerants.Extra InformationThis document provides an overview of alternative refrigerants - for more detailed informationrecommended reference materials are suggested at the bottom of each page. To avoid copyrightinfringement no part of international, European or national standards has been reproduced inthis document. Standards are an invaluable source of information so reference to them is madeand their use is strongly recommended.You should explore the Links folder on the home page to access the reference materialsrecommended when you have finished studying this module.The following refrigerants are included: R744 (carbon dioxide, CO2) R717 (ammonia, NH3 R32 (lower GWP HFC) R1234ze (low GWP hydro fluoro olefin) R290 (propane), R1270 (propene, propylene) and R600a (iso butane).

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Basic Properties

Basic PropertiesBrief historyR744, R717 and R290 were among the earliest refrigerants used for mechanical cooling systems.Their use declined when CFCs and HCFCs were developed and R744 and R290 were rarely used.R717 continued to be used in industrial systems.When the ozone depleting refrigerants1 were phased out R290 and other hydrocarbons started tobe used again. At the same time HFC refrigerants were introduced and widely used, but theirhigh global warming potential coupled with high leak rates in some applications has caused someof the industry to use lower GWP alternatives. These include R744 which has been used in retailsystems since the year 2000, and lower GWP HFCs which are now being trialled.Basic PropertiesThe basic properties of these refrigerants are shown in table 1 below.

Type Key facts GWP2 Sattemp3 Typical applications

R744 Carbon dioxide, CO2 Highpressures 1 -78CRetail refrigeration, heatpumps, integrals

R717 Ammonia, NH3Toxic andmildlyflammable

0 -33C Industrial

R32 Hydro fluorocarbon, HFCMildlyflammable 550 -52C Split air conditioning

R1234zeUnsaturated HFC(aka hydro fluoroolefin, HFO)

Mildlyflammable 7 -19C

Chillers, split airconditioning, integrals

R600a Isobutane, C4H10,hydrocarbon (HC) Flammable 3 -12CDomestic and smallcommercial systems

R290 Propane, C3H8,hydrocarbon (HC) Flammable 3 -42C Chillers, integrals

R1270Propene(propylene), C3H6,hydrocarbon (HC)

Flammable 3 -48C Chillers, integrals

Table 1, basic alternative regrigerant properties1. Chloro fluoro carbons (CFCs) and hydro chloro fluoro carbons (HCFCs)2. GWP is from EN378 -1:2008 + A2:2012, Annex E3. Sat temp is the saturation temperature at atmospheric pressure (1 barg), except for R744 where it is the surface temperature of solid R744 atatmospheric pressureSome of these refrigerants are already widely used, others are starting to be trialled anddeployed. Their application is often limited by flammability and toxicity - the table on the nextpage summarises the applications they are most suitable for.

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Application

Application of Alternative RefrigerantsThe table indicates the type of system the refrigerant is most appropriate for it does not showwhere these refrigerants are actually being used. The section below gives more information oncurrent applications.

Refrigerant Centralplant

VRV,VRF

Split AC /heatpumps

Chillers Remotecondensingunits

Integrals

R744R717R32R1234zeR600aR290 andR1270

Table 2, application of alternative refrigerants

Green these systems are suitable for the refrigerant type indicated, and the chargesize is usually within the limits specified in EN378. Some design changes are required,for example to electrical devices and / or ventilation.

Amber these systems can and are used with the refrigerant type indicated, but thereare restrictions because of the maximum charge or practical limit specified in EN378.Some design changes are required to electrical devices and / or ventilation. In somecases the volumetric capacity of the refrigerant means it is not ideal for theapplication.

Red these systems should not be used with the refrigerant type indicated, usuallybecause the charge size exceeds the maximum specified in EN378-1.

Alternative refrigerants are not suitable to be used in systems which are designed forconventional (non flammable) HFC or HCFC refrigerants.A brief introduction to each refrigerant or type of refrigerant is given on the next pages. For moredetails see the guide Design differences for alternative refrigerant systems.More information is available in the REAL Alternativese-library: See REAL Alternatives Guide 2, Design Differences with Alternative Refrigerant Systems

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Refrigerants

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R744

R744 (Carbon Dioxide, CO2)PropertiesR744 has high operating pressures, a low critical temperature(31C) and a high triple point. Its volumetric cooling capacityis between 5 and 8 times that of HFCs, reducing the requiredcompressor displacement and pipe size. Its properties have aneffect on how the system is designed and operates, especially inhigh ambient temperatures. It has a high dischargetemperature, necessitating two stage compression for lowtemperature systems. The document highlighted below hasdetailed information on how these properties effect theapplication of R744.

CO2 molecule

UsageR744 is used in the following system types: Pumped secondary where R744 is the secondary fluid cooled by a primary system. R744 is avolatile secondary which, coupled with the high capacity and density, reduces the required pumppower compared to other secondary fluids such as glycol. Cascade where the heat rejected by the condensing R744 is absorbed by the evaporatingrefrigerant in a separate high stage system. In these systems the R744 operates below thecritical point and the high side pressure is generally below 40 bar g. The high stage system canbe R744 (see below), or it can be HFC, HC, HFO or R717. Transcritical systems where the R744 heat is rejected to ambient air and at ambienttemperatures above approximately 21C the R744 will be above the critical point (31C) i.e. itwill be transcritical. The R744 does not condense it remains a super critical fluid until itspressure is reduced to below the critical pressure (72.8 bar g).The high side pressure is typically90 bar g when transcritical.Currently (2014) R744 has been used in several 1000 retail systems and in industrial systems inEurope. It is starting to be used in heat pumps and in integral systems.The application of R744 has required additional skills for design engineers and servicetechnicians, and availability of new components.

More information is available in the REAL Alternativese-library: NaReCO2 manual "Natural Refrigerant CO2 Danfoss Application Handbook "Food retil CO2 refrigeration systems" and "CO2 for industrialrefrigeration" Danfoss Application Handbook "Cascade HC/HFC-CO2 system" Danfoss CO2 Handbook Danfoss article "Transcritical refrigeration systems with CO2" Shecco Guide Europe 2013

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R717

R717 (Ammonia, NH3)PropertiesR717 has a relatively high saturation temperature atatmospheric pressure, is highly toxic, mildly flammable and hasa pungent odour. It can be smelt at concentrations of just 3 mg/m3, so it isevident at levels much lower than those which are hazardous(the ATEL / ODL is 350 mg/m3). It is the only commonly usedrefrigerant which is lighter than air which means thatdispersion of any leaked refrigerant takes place quickly.

NH3 molecule

R717 also operates with very high discharge temperatures. Single stage compression cantherefore normally be used above -10C evaporating temperature. Below this, two stagecompression with interstage cooling is required.The high toxicity limits the application of R717 to very low charge systems or industrial systems(i.e. systems in areas which are not accessible by the general public). This typically includesdistribution cold stores and food processing plants, usually using secondary systems where R717is the primary refrigerant.Ammonia corrodes copper so steel pipe work and open drive compressors are used. It is alsoimmiscible with conventional mineral oils, making oil rectification an additional requirement ofthe refrigeration systems. The use of steel pipe, open drive compressors and oil rectificationimpact on the capital cost of an ammonia installation.

More information is available in the REAL Alternatives e-library: Institute of Refrigeration Safety Code Ammonia

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R32

R32 (HFC)Properties R32 is a mildly flammable HFC. Its performance and operating pressures are very similar toR410A and it is starting to be used in similar applications heat pumps, split air conditioning systems and chillers.Its mild flammability limits the refrigerant charge size, but notto the same extent as the more flammable hydrocarbons.Electrical devices on the system will be the non sparking typeif a leak can result in a flammable concentration around theelectrical device. R32 molecule

The operating pressures are higher than for most HFCs, but are similar to R410A. Typically thehigh side maximum pressure is 35 bar g.

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R1234ze

R1234ze (HFO)PropertiesR1234ze is also a mildly flammable HFC, marketed as an HFO hydro fluoro olefin. This is a halocarbon containinghydrogen, fluorine and unsaturated carbon. It is in the samefamily of refrigerants as R1234yf which is now being used insome car air conditioning systems.Its mild flammability limits the refrigerant charge size, but notto the same extent as the more flammable hydrocarbons. Electrical devices on the system will be the non sparking typeif a leak can result in a flammable concentration around theelectrical device.

R1234ze molecule

R1234ze is not yet widely available, but is being trialled in chillers and integral units.Several blends using R1234ze are available for testing. They have lower saturation temperaturesso are suitable for low temperature applications. They all have GWPs in excess of 300. Someare non-flammable, but these tend to have significantly higher GWPs.

More information is available in the REAL Alternatives e-library: Bitzer Refrigerant Report 17 Honeywell leaflet: Solstice a full range of refrigerant solutions

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R290 R1270 R600a

R290, R1270 and R600a (HCs)R290 (propane), R1270 (propene, propylene) and R600a (isobutane) are all hydrocarbons. They are highly flammable, so refrigerant charge size is limited on many applications. This limitsthe application of HCs mainly to integral systems, chillers and some split air conditioningsystems. Electrical devices on the system will be the non sparking type if a leak can result in a flammableconcentration around the electrical device.

Propane molecule

Propene molecule

Isobutene molecule

R290 and R1270 have similar performance and operating pressures to R404A and they are usedin high, medium and low temperature commercial applications. R600a has a much higher saturation temperature than other refrigerants and operates at avacuum on the low side in most applications. Its use is limited to domestic and very smallcommercial refrigeration systems with minimal leakage so that ingress of air and moisture due toleakage rarely occurs.Blends of HCs are also available, such as Care 30 (propane and isobutene) and Care 50 (propaneand ethane). They are also highly flammable, and have significant temperature glide.

More information is available in the REAL Alternatives e-library: Institute of Refrigeration Safety Code for Flammable Refrigerants

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Safety

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Pressures

PressuresThe charts in figures 1 and 2 show the saturation temperature / pressure relationship for thealternative refrigerants as well as R404A and R134a:

Figure 1, pressure temperature, lowand medium pressure refrigerants

Figure 2, pressure temperature,high pressure refrigerants

Most of the alternative refrigerants operate with lower pressures than R404A, thus enablingstandard tools and equipment to be used (unless these are inappropriate for other safety reasonssuch as flammability or material compatibility such as with ammonia).However, R32 and R744 operate with higher pressures: The maximum condensing pressure in R32 systems is typically 35 bar g; The maximum high side operating pressure in R744 transcritical systems is typically 90 bar g.This is not shown in the pressure temperature chart above because it is above the criticaltemperature of 31C. It is a function of either the control setting (for example in a central plantsystem used in the retail sector) or of the quantity of refrigerant in the system (in a typicalintegral type system); The maximum condensing pressure in R744 cascade systems is typically 35 bar g.The higher operating pressures have an effect on: The rating of the components used; Pipe thickness; Tools used to access the system; Refrigerant recovery equipment. Mostly the required components, tools and equipment arenow readily available but it is essential that the appropriate tools, components and equipmentare used and are compatible for the refrigerant in use.

More information is available in the REAL Alternatives e-library: Danfoss Refrigerant Slider App tool Bitzer PT App tool

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Tables

Flammability Classification and Safety Information

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Flammability Classification and Safety InformationFlammability classificationSafety classification Lower

Flammability level,% in air by volume

Heat ofcombustion, J/kg

Flame propagation

1 No flame propagation when tested at 60C and 101.3 kPa2, lowerflammability

> 3.5 < 19,000 Exhibit flame propagation when tested at 60C and 101.3 kPa

2L, lowerflammability,proposed subclassification

> 3.5 < 19,000 Exhibit flame propagation when tested at 60C and 101.3 kPa and have a maximumburning velocity of 10 cm/s when tested at23C and 101.3 kPa

3, higherflammability

3.5 19,000 Exhibit flame propagation when tested at 60C and 101.3 kPa

Table 3, safety classificationNote it is proposed to include the 2L safety classification in revisions of EN 378, ISO817 and ISO5149. It is already used in ASHRAE standards (American Society of Heating,Refrigeration and Air Conditioning Engineers) and is in de facto use, so it is included inthis document. To highlight that it is not yet in the standards referenced here it will beshown as A2L (proposed) in the text of this document. Safety informationRefrigerant Safety group a LFL, kg/m3 b Auto ignition temp,

CPL, kg/m3 c ATEL / ODL d

CO2R744 A1 Not applicable Not applicable 0.1 0.07NH3R717 B2L (proposed) 0.116 630 0.00035 0.00022HFCR32 e A2L (proposed) 0.307 648 0.061 0.30HFOR1234ze f A2L (proposed) 0.303 368 0.061 0.28HCR600a A3 0.043 460 0.011 0.06HCR290 A3 0.038 470 0.008 0.09HCR1270 A3 0.047 455 0.008 0.002

Table 4, safety informationa. The safety group is as listed in EN378-1. b. LFL (kg/m3) is the Lower Flammability Limit as listed in EN378-1. c. PL is the Practical Limit as listed in EN378-1. For A1 refrigerants it is the highestconcentration in an occupied space that will not result in escape impairing effects. For A3refrigerants it is approximately 20% LFL. d. ATEL / ODL is the Acute Toxicity Exposure Limit / Oxygen Deprivation Limit as listed inEN378-1. This is the level above which there is an adverse effect that results either froma single or multiple exposures in a short space of time (usually less than 24 hours). e. The information for R32 is from the current proposed revision of EN378. f. R1234ze is not listed in the current version of EN378. The information is based on thecurrent proposed revision. R1234ze does not exhibit flame limits under standard testconditions, but it does at temperatures above 30OC. The LFL stated is at 60OC.

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Flammability Classification and Safety Information

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Classification

Safety ClassificationSafetyAll alternative refrigerants covered in this guide have safety issues beyond those of the HFCrefrigerants.These include: Flammability mild (HFOs, R32 and R717) and high (HCs); Toxicity low (R744) and high (R717); High pressures (R744). Toxicity and flammabilityThe safety classifications below are defined in ISO817:2009 and are also used in EN378-1:2008A2:2012.

ClassificationThe classifications comprise two parts: A or B represents the degree of toxicity; 1, 2, 2L or 3 represents the degree of flammability.The toxicity classification is as follows: Class A is lower toxicity(most refrigerants are class A); Class B is higher toxicity(R717 is class B).

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Restriction on use

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Indirect Systems

Maximum charge for indirect systemsThe table below summarizes the information in the extensive tables in EN378 - you should refer to the standard fordetailed information.

Area beingcooled 1

System location Max charge,A1refrigerants

Max charge, A2refrigerants

Max charge,A3refrigerants

Max charge, B2refrigerants

All areas Part or all ofsystem belowground

As below As below 1 kg As below

Generaloccupancy -class A

Human occupiedspace and occupiedmachine rooms

Considered adirect system

Considered a directsystem




Compressor andreceiver in anunoccupiedmachine room or inthe open air

No restriction PL x room volumeor comfort coolinglimit

1.5 kg PL x room volume


Whole of system inan unoccupiedmachine room oropen air

No restriction No restriction if exitto open air and nodirectcommunication withA and B

5 kg No restriction ifexit to open airand no directcommunicationwith A and B

Supervisedoccupancy class B









2.5 kg No restriction




10 kg No restriction

Authorisedaccess classC








No restriction No restriction 25 kg No restriction



No restriction No restriction No restriction No restriction

Table 6, maximum charge for indirect systems1. Area being cooled, see table 7 below for full explanation and examples. If there is morethan one category of occupancy the more stringent applies. If occupancies are isolated fromeach other the requirements of the individual category applies.There is no restriction unless the system is located below ground or on upper floors with inadequate emergency exit.The cells shaded in orange apply to non comfort cooling and heating applications only.

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Direct Expansion Systems

Maximum charge for direct expansion (DX) systemsThe table below summarizes the information in the extensive tables in EN378 - you should refer to the standardfor detailed information.

Area beingcooled 1

System location Max charge,A1refrigerants



Max charge,B2refrigerants

All areas Part or all of systembelow ground

See below As below 1 kg As below



PL x roomvolume

38 x LFL 1.5 kg PL x roomvolume


Compressor andreceiver in anunoccupied machineroom or in the openair

PL x roomvolume

38 x LFL 1.5 kg PL x roomvolume



No restriction 132 x LFL 5 kg 2.5 kg



PL x roomvolume 2 or norestriction

10 kg 2.5 kg 10 kg



No restriction 25 kg 2.5 kg 25 kg



No restriction No restriction 10 kg No restriction



PL x roomvolume * or norestriction

10 kg, or50 kg if < 1person per 10m2

10 kg 10 kg, or50 kg if < 1person per 10m2



No restriction 25 kg, orno restriction if< 1 person per10 m2

25 kg 25 kg, orno restriction if< 1 person per10 m2



No restriction No restriction No restriction No restriction

Table 5, maximum charge for direct expansion (DX) systems1. Area being cooled, see table 7 below for full explanation and examples. If there ismore than one category of occupancy the more stringent applies. If occupancies areisolated from each other the requirements of the individual category applies.There is no restriction unless the system is located below ground or on upper floors with inadequate emergencyexit.The cells shaded in orange apply to non comfort cooling and heating applications only.

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Maximum Charge Size

Restrictions on use - such as maximumcharge size

EN378 provides practical limits and maximum charge sizes for refrigerants. The practical limitsare shown in table 4 and are based on the dominant hazard of the refrigerant: Toxicity (R717); or Flammability (R600a, R290, R1270, R32, R1234ze); or Asphyxiation (R744).The practical limit (PL) is the highest concentration level in an occupied space that will not resultin escape impairing effects. Where flammability is the dominant hazard it is 20% of the lowerflammability level. PL is used to determine the maximum charge size for the refrigerant forsystems where the refrigerant can leak into an enclosed occupied space.EN378 specifies maximum charge sizes which depend on: Location of equipment, e.g. below or above ground level, within cooled space, in machine room; Occupancy of area being cooled, e.g. unrestricted access by the public or authorised accessonly; Type of system, e.g. direct expansion or secondary / refrigeration or air conditioning.

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Comfort cooling/heating

Maximum charge for comfort cooling andheating

For comfort cooling and heating the maximum charge is found from the following equation:M = 2.5 x LFL1.25 x h x AWhere: M = max charge, kg LFL = lower flammability limit, kg/m3 (0.038 for R290, 0.040 for R1270) h = height of unit, m (0.6 for floor mounted, 1.0 for window, 1.8 for wall, 2.2 for ceiling) A = floor area, m2

Class Location where ExamplesA People may sleep;

The number of people present is not controlled;Any person has access without being personallyacquainted with the personal safety precautions

Hospitals and nursing homesPrisonsTheatres, lecture hallsSupermarkets, restaurants, hotelsTransport terminiIce rinks

B Only a limited number of people may beassembled, some of them being necessarilyacquainted with the general safety precautions.May be a room or part of a building.

LaboratoriesPlaces for general manufacturingOffice buildings

C Not open to the general public where onlyauthorised persons are granted access.Authorised persons are acquainted with generalsafety precautions.

Cold stores and abattoirsRefineriesNon public areas in supermarketsManufacturing facilities (e.g.chemicals, food)

Table 7, occupancy classification

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Examples

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Ex.1 - Non Comfort

Example 1 - Non comfort cooling / heatingNon comfort cooling or heating: An example ofthe application of the practical limit for R290 in asmall walk in cold room is shown below: Cold room size 3.5 m by 3 m by 2.4 m high; Cold room volume = 3.5 x 3 x 2.4 = 25.2 m3; R290 practical limit = 0.008 kg/m3;Maximum charge = practical limit x room volume= 0.008 x 25.2 = 0.202 kg.

Source: http://www.air-rite.com.au

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Ex.2 - Comfort

Example 2 - Comfort cooling / heatingAn example of the comfortcooling / heating equation isfor a room cooled by anR1234ze split air conditioningsystem with a ceiling mountedindoor unit is shown below: LFLR1234ze = 0.303 kg/m3 h = 2.2 for ceiling mountedunit A = 9 m x 5.5 m = 49.5 m2M = 2.5 x 0.3031.25 x 2.2 x49.5M = 3.95 kg.

Source:http://www.airconditioninstallationbrisbane

.com.au

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Min. Room Volume

Determine Minimum Room VolumeThe two calculations above can also be used to determine minimum room volume for a systemwith a specific charge.

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Performance and Operating Conditions

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Performance Comparison

Performance ComparisonThe table below provides an indication of performance of the alternative refrigerants. R404A isincluded for comparison purposes. This information has been derived from CoolPack softwareexcept where specified.The figures below provide an indication of comparative performance as it is based on atheoretical cycle. Actual comparisons depend on compressor technology, application, ambientand system type. Manufacturers data / software will provide a more accurate comparison for aspecific application.This is especially so for R744 where expected COP, for example, would be higher than indicatedbelow for the type of system and operating conditions where R744 is typically deployed.

RefrigerantSaturationtemperatureat 0 bar g,C

Requireddisplacementm3/h

COP Dischargetemperature,C

Compressionratio a

R404A -46 14.84 2.94 57 3.82R744 -78 3.88 1.75 c 114 3.42R717 -33 14.3 3.27 152 4.82R32 b -52 9.65 3.17 99.5 3.77R1234ze b -19 35.14 3.28 52 4.54R600a -12 47.13 3.26 51 4.40R290 -42 17.35 3.18 59 3.61R1270 -48 14.3 3.17 67 3.53

Table 8, performance comparisona. Compression ratio is the discharge pressure divided by the suctionpressure, both in bar absb. Data from Refpropc. All the COPs given in this table are theoretical COP of the refrigerationcycle. R744 operates above the critical point at the reference cycle, inpractice the COP will be higher than shown in the simple comparison above.ConditionsThe comparison has been estimated at the following conditions: Cooling capacity, 10kW Evaporating temperature, -10C Condensing temperature, 35C (R744 is trans critical and has a gas cooler exit temperature of35C) Useful superheat, 5K Subcooling, 2K Pressure losses are equivalent to 0.5K Isentropic efficiency, 0.7

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Performance ComparisonMore information is available in the REAL Alternativese-library: Coolpack Software Bitzer selection software Bitzer Refrigerant Report 17; pages 36, 37 Copeland Select 7 Software

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Charts

Displacement and COP ChartThe charts below show the displacement required for a given cooling capacity and the COPcompared to R404A at the above operating conditions.Click on the images below to see them in full size.

Figure 3, displacement compared toR404A Figure 4, COP compared to R404A

Note that the COP for R744 is low because this is a theoretical cycle comparison at conditionswhich most refrigeration systems would operate (including 35C (condensing temperature).However, R744 is above the critical temperature for this comparison, and in reality the headpressure would be controlled to a different pressure to provide improved COP.

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Environmental Impact

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GWP

Global WArming Potential (GWP)The date in table 1 provides the direct global warming potential (GWP) of the alternativerefrigerants. This should not be considered in isolation when selecting a refrigerant for aparticular application. The impact of the refrigerant GWP is much less if the refrigerant doesnot leak during normal operation and the system is serviced without refrigerant loss. However,the revision of the F Gas regulation will necessitate the application of low GWP refrigerants.Click on the images below to see them in full size.

Source:http://www.climatechoises.org.uk

source:http://www.howstuffworks.com

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TEWI

TEWIThe total impact of a system and refrigerant on climate change is estimated using TEWI theTotal Equivalent Warming Impact. It is a method of assessing the impact on climate change overthe lifetime of a system by combining:the direct contribution of refrigerant emissions into the atmosphere+the indirect contribution of the CO2 resulting from energy to operate the systemIt is a very useful method of comparing different system and refrigerant options at the designstage or when considering a retrofit, for example from R22.

There are many ways TEWI canbe minimised, including: Minimising refrigerant leakage(which reduces both the directand indirect impact becauseleaking systems use moreenergy); Use of low GWP refrigerants; Minimising cooling load; Maximising energy efficiencythrough appropriate design andinstallation; Maintaining the systemcorrectly; Minimising refrigerant lossduring service; Recovery and recycling of usedrefrigerant (and used insulationwhere this has a blowing agentwhich has a GWP).

Refrigerant leakage detection

source: http://www.traceerline.com

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TEWI calculation

TEWI CalculationTEWI is calculated as follows:TEWI=impact of leakage losses+impact of recovery losses+impact of energy consumptionWith: Impact of leakage losses = GWP x L x n Impact of recovery losses = GWP x m x (1-recovery) Impact of energy consumption = n x Eannual x Where: L = leakage in kg/year n = system operating time in years m = refrigerant charge in kg recovery = recovery / recycling factor, between 0 and 1 Eannual = energy consumption in kWh per year = CO2 emission in kg / kWh, note this varies significantly from country to country.

Specific TEWIMany of the factors used in this calculation vary significantly and are system specific. You candecide the factors for yourself from your own experience (for example leakage), use knownfactors (for example for ) or use industry recommended factors such as those available in theUK from the British Refrigeration Association.To more accurately compare very different system options it is useful to use specific TEWI:TEWI / (Euseful cooling + Eheating + Eheat reclaim)Where: Euseful cooling is the useful cooling capacity (cooling systems) in kWh/year Euseful heating is the useful heating capacity (heat pumps) in kWh / year Eheat reclaim is the useful heat reclaim in kWh / year.

More information is available in the REAL Alternativese-library: British Refrigeration Association Guideline Method for Calculating TEWI TEWI calculation software and downloads available from SKN Sweden

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Availability

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Availability

Availability of refrigerant, components,information and

skilled engineers / technicians

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skilled engineers / techniciansThe table below gives an indication of how widely available important aspects of alternative refrigerantsystems are. The simple traffic light system provides a quick reference to availability and hence currentease of deployment.

Refrigerant Knowledge Skills /Training ComponentsTools andequipment

R744

Refrigerantgrade CO2available in arange ofcylinder sizes

Wide range ofsystem designoptionschallenge designengineers

Hazards andrange ofsystem typeschallengetechnicians.Trainingavailable

Available forlarge systems,less so for smallsystems

Available

R717

Refrigerantgrade NH3widelyavailable in arange ofcylinder sizes

Widelyunderstood inthe industrialsector

Widelyunderstood inthe industrialsector.Trainingavailable

Widelyavailable in theindustrialsector

Widelyavailable

R32 AvailableManufacturers ofR32 equipmenthave a goodunderstanding

Very littleexperience andquestionsregardingsources ofignition. HCtrainingapplicable andavailable

To be deployedin AC systemsfrom 2015

Widelyavailable(most HCtools /equipmentare suitable)

R1234ze Available onlyin trialquantities,expensive

Very limitedknowledge

Very limitedexperience, butHC experienceis applicable.HC trainingapplicable andavailable

Compressorsnot readilyavailable

Widelyavailable(most HCtools /equipmentare suitable)

R600a

Refrigerantgrade HCsavailable in arange ofcylinder sizes

Widely used andunderstood inthe domesticsector

Very wideexperience inthe domesticsector. Trainingavailable

Widelydeployed,componentsreadilyavailable

Widelyavailable,exceptrecoverymachine isavailablefrom only onesupplier

R290 Informationreadily availableon application ofHCs incommercialsystems

Wideexperience inthe commercialsector.Trainingavailable

Widelydeployed inintegralsystems andchillers,componentsreadilyavailable

R1270

Table 9, availability of alternative refrigerants and associated items

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skilled engineers / technicians

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Leakage Issues

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Leakage Issues

Leakage IssuesThis section outlines issues associated with leakage of alternative refrigerants more detailedinformation is provide in REAL Alternatives Guide 3, Containment and Leak detection forAlternative Refrigerants.Whatever refrigerant is used leak potential should be minimised. Low GWP alternativerefrigerants usually have hazards associated with high pressure, flammability or toxicity, soleakage is a safety concern. In addition any leaking system consumes more power and so has agreater indirect impact on climate change.The potential for leakage is a combination of factors such as operating pressure, molecule sizeand system size / type. This is summarised in the table below, with hazards associated withleakage and ease of leak detection.

Refrigerant Leak potential Hazards Ease of detection

R744

High High operating pressures Used in large systems withmultiple joints Vented during service

High pressuresduring operationand standstill

Good detectionequipment available

R717

Medium Medium to low operatingpressures Usually used in chiller typesystems with minimum joints Open compressors with shaftseals

Toxicity and mildflammability

Good - odour anddetection equipmentavailable

R32

Medium Medium to high operatingpressures Used in AC systems, butusually with brazed connections

Mild flammability Detection equipmentbecoming available

R1234ze

Medium Medium to low operatingpressures Used in chiller type systemswith minimum joints

Mild flammability Detection equipmentbecoming available

R600aR290R1270

Low Medium to low operatingpressures Used in systems with lowcharge in line with requirementsfor A3 refrigerants

High flammability Detection equipmentavailable

Table 10, leak potential, hazards and ease of leak detectionMore information is available in the REAL Alternativese-library: REAL Alternatives Elearning Module or Guide 3 - Containment and Leak detection for AlternativeRefrigerants KHLim-inet 41 / 47

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Standards and Legislation

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Standards and Legislation

Outline of relevant standards and legislation

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Outline of relevant standards and legislationThe table below shows the most useful standards and regulations relevant to the application of alternativerefrigerants. More information and links to these documents will be available in the REAL Alternatives e-library in aspecial guidance note on legislation to be added shortly.

Document Title Guidance (relevant to flammablerefrigerants)

ISO 817:2005 Refrigerants -- Designation system An unambiguous system fornumbering refrigerants. It includessafety classifications (A1, A2, A3).

EN 378-1:2008A2:2012

Refrigerating systems and heat pumps Safetyand environmental requirements, Basicrequirements, definitions, classification andselection criteria

Practical limitMaximum charge sizes

EN 378-2:2008A2:2012

Refrigerating systems and heat pumps Safetyand environmental requirements, Design,construction, testing, marking anddocumentation

High pressure protectionVentilated enclosures

EN 378-3:2008 Refrigerating systems and heat pumps Safetyand environmental requirements, Installationsite and personal protection

Machinery roomsRefrigerant detectors

EN 378-4:2008A2:2012

Refrigerating systems and heat pumps Safetyand environmental requirements, Operation,maintenance, repair and recovery

Repairs to flammable refrigerantsystemsCompetence of personnel working onflammable refrigerant systems

EN 60079-0:2009

Explosive atmospheres Equipment generalrequirements

Categorisation of flammable gasesClassification of equipmentZones

EN 60079-10-1:2009 Explosive atmospheres Classification of areas explosive gas atmospheres

Zones and classification of equipmentLeak simulation testingAir flow requirements

EN 60079-14:2008 Explosive atmospheres Electricalinstallations design, selection and erection

Location of sources of ignitionWiring

EN 60079-15:2010 Explosive atmospheres Equipment protectionby type of protection n

Electrical equipment and enclosuresfor use in potentially flammable areasLabelling of electrical equipment

EN 60335-2-24:2010 Household & similar electrical appliances SafetyPart 2-24: Particular requirements forrefrigerating appliances, ice-cream appliances& ice-makers

Systems with less than 150 gflammable refrigerant charge.

EN 60335-2-40:2003 Household & similar electrical appliances Particular requirements for electrical heatpumps, air conditioners and dehumidifiers

Design, application and servicing ofAC systems using flammablerefrigerants.

EN 60335-2-89:2010 Household & similar electrical appliances SafetyPart 2-89: Particular requirements forcommercialrefrigerating appliances with an incorporatedorremote refrigerant condensing unit orcompressor

Systems with less than 150 gflammable refrigerant charge, leaksimulation testing for areaclassification.

ADR European Agreement concerning theInternational Carriage of Dangerous Goods byRoad

Transport of flammable gases insystems or equipment by road

RID Regulations concerning the internationalcarriage of dangerous goods by rail

Transport of flammable gases insystems or equipment by rail

Table 11, standards and regulations

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Outline of relevant standards and legislation

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What's next?

What happens nextThe information in this guide provides an introduction to the most common alternativerefrigerants. You can now go back and review any of the areas that you would like to revisit and go to thee-library to access more detailed information.When you are ready, you can take a sample multiple choice assessment to check that you haveunderstand some of the key points in this module by using the TEST button in the home page. Note - The TEST page only provides a sample of the questions which will be linked to thecontents of the module. When the piloting and been completed the full assessment will consist ofa single 40 question multiple choice assesment covering the material in all of the first fourmodules. The assessment will be available via a network of registered training providers.After you have completed the TEST please fill in the EVALUATION SURVEY (of module 1) athttps://www.surveymonkey.com/s/DW9DRLG to give your feedback on this trial version of thee-learning and assessment.

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module 1 - introduction to alternative refrigerants

Documents

earliest refrigerants

following refrigerants

time hfc refrigerants

lower gwp alternatives

basis of low gwp

lower gwp hfcs

industrial systems

designed systems