SWEP offers a full range of BPHEs engineered to deliver the highest COP and the lowest life-cycle cost in all the applications included in refrigeration. This is particularly applicable to the supermarket and transport sectors.
Cooling food in supermarkets or cooling buildings with air-conditioners, reusing waste heat in desuperheaters and heating houses with heat pumps – these are all examples of what is the largest application field for SWEP BPHEs, i.e. Refrigeration applications.
The theory behind refrigeration phenomena may seem complicated. So the purpose of the refrigeration applications handbook is to make this theory accessible and easier to understand. The handbook is a powerful tool for learning more about the background to heat transfer.
During the last decade we have seen, in parallel with traditional DX systems, the constant expansion of new technologies with CO2 as the refrigerant and as the secondary coolant media. Supermarket systems are divided into two temperature levels, MT and LT:
MT: display cabinets and cold rooms at +6 to 0 °C
LT: display cabinets and cold rooms at -18 to -24 °C
Systems are designed to suit these two temperature levels. In northern Europe we have seen the progressive introduction of transcritical booster systems, using CO2 as the refrigerant, in both MT and LT. In other countries, hybrid systems are becoming a standard solution. In these systems, R134a and R1234ze are, normally, the refrigerants used in MT, and CO2, condensed via a cascade BPHE, is the refrigerant used in LT. Pumped systems using CO2 as the coolant media are used in hot countries, due to the cost savings in pipe sizing and the increased efficiency. In emerging markets, supermarket systems are normally manufactured using brine chillers, with the glycol circulation ensured via a centrifugal pump.
In these refrigerated systems, the main challenge is the units' large operational envelope. The required temperature is normally between +7 °C and -24 °C. Applications identified for our products are:
Suction gas heat exchanger
The reason for installing these BPHEs is related to the increased system efficiency that can be achieved with these additional features – an increase that justifies the increased circuit complexity. The refrigerants involved are R134a, R1234ze, R452B and R404A. Interesting case studies and prototypes are currently ongoing using CO2 to substitute synthetic refrigerants. In these cases, a transcritical cycle is considered.