S R C C Alternatives to H F s in the efrigeration and Air Conditioning Sector ection 01 19 Chillers are systems that indirectly cool a building or a process. Typically they are used in larger systems and the “cooling” distributed with water or a mixture of water and anti-freeze when it is necessary to work at low temperatures. Chillers are mainly factory-built units that are intended to cool a liquid such as water or, if a lower temperature is desired, fluids with lower freezing points. Chillers can be air-cooled, i.e. where the condenser is directly cooled by air, or water-cooled, where the condenser is cooled by circulating water (possibly with freeze depression if the climate is such that the water would risk freezing in the winter). Their main applications are for air conditioning in larger buildings, i.e. hotels, offices, hospitals, military complexes, etc. or for process cooling in various industries. This solution is often associated with a higher investment cost than solutions with split systems for air conditioning or smaller units for each object in need of cooling in the industry. In many cases, small non-chiller RAC units can be installed gradually and often by tenants, thus eliminating the need for the owner to invest and charge costs to the tenants. Central systems with chillers are often preferred in larger systems where the possibilities of more stable operation by balancing cooling loads over time (as the loads are not occurring simultaneously over the whole building), reducing maintenance cost are preferred as it also avoids noise and/or esthetical drawbacks of having large numbers of split/unitary systems. This option is often used in larger buildings operated by owners with the capability to invest in more long term solutions. Chillers are globally used in central air conditioning systems where R-22 is one of the most commonly used refrigerants, apart from CFCs 1.2.4 ChChillers in air conditioning and cooling appappapplications (including heat pupumps with indirect systems). 1.2.3 VRV/VRF/multi-split systems (including heat pupumps)which are still present in large quantities in the old chiller equipment in both developed and developing countries. Apart from their use in the air conditioning sector, HCFC chillers using R-22 are also common in the food processing industry as well as in other industries where processes need to be cooled. At one point a large chiller segment using R-11 was to some extent converted to R-123 which is an HCFC, but has low ODP and low GWP. At the time this report was Pumpsecondary fluid i.e.water/glychol/brine/CO2Refrigerant inside: NH3, HC or HFCAir or liquidcondenser Fig. 1.3 Chillers use secondary fluid to indirectly cool the room or object. Th ese are systems that have been developed from the split systems (Daikin Industries developed and launched “Variable Refrigerant Volume” and protected the use of the acronym “VRV” so other manufacturers use “VRF” for Variable Refrigerant Flow). These system designs are characterised by one unit cooling (and sometimes heating) several rooms and adapting its capacity to the variations in the demand. These units have a lot in common with split systems, but are dependent on complex electronic controls and have an intricate design, which will make them more difficult to retrofit. This is because oil transport and control behaviour could be affected and difficult to predict unless there is access to design info and proper test facilities or support from the manufacturer. For obvious reasons, the manufacturers are rarely interested in investing the resources required to extend the life of existing equipment. S implified flowchart: chiller