CHILLERS REFRIGERANTS


Plant rooms for chillers with large hydrocarbon charges can be designed and used safely through proper refrigerant handling


concentration, or LOC. Determinations of LOC are made using the ASTM E2079 Standard TestMethod for Limiting Oxygen (Oxidant) Concentration inGases and Vapours. The limit of flammability is determined by specific pressure rise criteria of the test standard. Once hazard studies are completed, this


will allow the application of hydrocarbon chillers anywhere in a building, finally bringing to an end the dominance of halocarbon refrigerants for building air conditioning applications.


l NICHOLAS COX is managing director at Earthcare Products Ltd. www.earthcareproducts.co.uk


References 1. Directive 2006/40/EC of the European parliament dated 17 May 2006 and amending council directive


70/156/EEC (the MAC directive) has commenced phase-out of hydrofluorocarbon (HFCs) refrigerants from mobile air conditioning systems. Regulation (EC) No 842/2006 of the European parliament and of the council (the F-Gas regulation) imposes restrictions on the use of HFC refrigerants in stationary systems. The UK has transposed the EC regulation through its 2009 GB F-gas regulation, which came into force in March 2009. There was a review of the EC Regulation in 2011 and the results of the consultation process have just been published (Please see: http://ec.europa. eu/clima/consultations/0011/summary_en.pdf). As a result of this, further activity by the European Community and its member states regarding the reduction of greenhouse gases including HFCs is expected very shortly.


2. Natural Refrigerants Sustainable Ozone- and Climate-Friendly Alternatives to HCFCs, GTZ Proklima, 2008; EC International Technical Meeting on HCFC phase-out, 05-06 April 2008, Atmosphere 2010 International Workshop on Natural Refrigerants Brussels 27-28 September 2010.


3. See the EU regulation BS EN 378-3; the Institute of Refrigeration code of practice for A3 refrigeratants; the ACRIB guidelines for flammable refrigerants; and the GTZ Proklima guidelines for the safe use of hydrocarbon refrigerants.


Efficiencies Example of HC technology SAFETY FACTORS


The safety principles relating to the use of hydrocarbon refrigerants in external air- cooled water chillers are:


Electrics should be sealed (to at least IP54) or non-sparking (i.e. solid state);


Access to the equipment must be restricted to authorised personnel only (although this is best practice regardless of refrigerant);


Clear labelling of the refrigerant and hazards;


Mechanical or natural venting to prevent gas accumulating inside the chiller and consideration of gas leak detection; and


Steps must be taken to ensure that refrigerant cannot leak into the building.


Further energy efficiency improvements are predicted with the development of a vapour injection economised screw with inverter part load controls:


% Capacity 100 75 50 25


CoP (with inverter) 4.0 4.6 5.1


6.0


Part-load efficiency data – 420 kW air-cooled chiller


% Capacity


100%: 4.0 x 0.03 75%: 4.6 x 0.33 50%: 5.1 x 0.41 25%: 6.0 x 0.23 SEER


CoP (with inverter) 0.12 1.52


2.09 1.38 5.11


Seasonal Energy Efficiency Ratio – 420 kW air cooled chiller


Even higher efficiencies can be achieved with evaporative condensers or cooling towers:


% Capacity 100 75 50 25


CoP (with inverter) 5.09 5.48 6.44 6.78


Part-load efficiency data – 950 kW water-cooled chiller


% Capacity


100%: 5.09 x 0.03 75%: 5.48 x 0.33 50%: 6.44 x 0.41 25%: 6.78 x 0.23 SEER


CoP (with inverter) 0.15 1.81


2.64 1.56 6.16


Seasonal Energy Efficiency Ratio – 950 kW water- cooled chiller


Efficient, flexible chillers


As the UK’s number 1 provider of chiller and precision air conditioning solutions, we are experts in integrating and optimising our products to reduce your total cost of ownership.


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T: +44 (0) 113 238 7735 E : f.farrelly@airedale.com W: www.airedale.com/efficientchillers


48


CIBSE Jun12 Chillers 65x190mm snake v1 with notes.indd 1 CIBSE Journal June 2012


SmartCool OnRak INTEGRATED CONTROL SOLUTIONS 11/05/2012 11:06 www.cibsejournal.com


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