Hybrid Condensers and their Advantages in Ammonia Systems

Energy and water costs affect the operation and design of an ammonia refrigeration system. Aircooled condensers consume more energy than evaporative condensers, but also increase the energy consumption of the compressor because of the higher condensation pressure. However, even though evaporative condensers consume less energy, they also consume water. When water costs are high, hybrid condensers, which are cooled by water when temperatures are high and cooled by air when temperatures are low, may be a viable solution. This paper analyzes and compares the energy and water costs of 3 refrigeration systems, each with a different condenser, using Bogota, Colombia as an example, to calculate the hourly consumptions based on the historical ambient temperatures for a sample year. In this case, because of the high water costs in Bogota and the distribution of ambient temperatures, the lowest operating cost option is the hybrid condenser. However, the payback period compared to an evaporative condenser is 8-10 years. This payback period depends on water costs and can be reduced to half if water costs increase by 10%. In the future, water costs will continue to increase in many cities making the analysis made for Bogota more and more relevant.