Waterloop System / Aqualoop system
In the last few years, a new system has been gaining ground in the commercial refrigeration market, involving a water loop with variable speed compressors. This system represents a change in approach compared to traditional systems.
Traditional systems are centralised, with compressor racks - generally installed in equipment rooms or on the roof of the building - that supply refrigerant to the evaporating units (showcases and cold rooms inside the store) via long copper pipes.
The water loop solution, on the other hand, is a distributed system: the refrigeration units feature small water-cooled condensing units fitted with variable-speed compressors. A simple water circuit is used to carry away the heat or transfer it to the outside via a drycooler.
1. Firstly, the supermarkets that have started using this solution have seen considerable energy savings. The three key elements are the plugin unit concept, the efficiency of DC compressors with permanent magnet motors, and the effect of variable-speed. In a centralised system, a line of refrigerated showcases operates so as to meet the needs of the unit with the highest demand; this forces work the compressor racks to work in generally worse conditions. The use of plugin showcases means the operating conditions of each unit are independent and the board on each can consequently operate in more favourable conditions than the compressor racks in a traditional system. Permanent magnet DC motors are more compact than corresponding AC motors, require less energy to magnetise the rotor and thus in general consume around 5% less power in the same conditions. On a showcase, load varies depending on the time of day, the season, following defrosting or when loading the goods. The possibility to change compressor speed means that unit cooling capacity can be adapted based on actual demand. In this way, the compressor works most of the time in conditions that maximise COP, without affecting temperature control.
5. One of the market trends in commercial refrigeration is a shift in investments from large hypermarkets to local stores, which are smaller, less standardised and easier to setup in old town centreswhere space and noise problems may prevent the opening of traditional stores. Not using compressor racks solves the problem of both space (moreover allowing a larger selling area) and noise.