District cooling
District cooling is the opposite of district heating in that water temperature is lowered not raised. The cooled water is fed into networks that are similar to district heating networks. The big advantage of district cooling is that it dramatically reduces energy costs as the cold is not produced in small, ineffective air conditioners, but in large compression refrigerators, which work very efficiently due to regular maintenance and oversight.
Delivery of cold water
The required cold is generated in a refrigeration unit and delivered to the consumer via insulated piping networks. The term „cold delivery“ is somewhat misleading. Technically excess heat is taken from the customer. The supply temperature in the network is about 6 ° C. Excess heat, for example from air-conditioning units, is taken from the customer and supplied either directly or indirectly to the network. The return temperature is therefore higher than the input temperature, 12 ° C or more. This excess heat is removed from the cooling network via refrigeration systems. The main components of such refrigeration systems are the refrigeration units themselves.
Use of district cooling
In many areas equipped with district heating systems, facilities with high refrigeration demand use absorption refrigerators run on the district heating system. In winter hot water is delivered to the customer and cold is generated on site. This makes sense as electrically operated air conditioning systems need to operate with great efficiency, especially at peak-load times.
Space saving and simple operation
As there is no need for an electrical power supply no space is needed for transformer stations or cooling stations. This can free up valuable rental space. District cooling systems also generate less noise, less vibration and fewer electrical interference fields. This makes them extremely well suited for use in large hospitals or similar facilities.
Reduction of emission and conservation of resources
District cooling absorption refrigerators require electricity only for auxiliary power. This means that fossil fuel use can be considerably reduced. Absorption refrigerators require only a tenth of the fossil fuel needed by modern compression coolers. District cooling can save up to2.5 times more CO2 than conventional systems. Another positive effect on the environment is that the waste heat – instead of heating up rivers and the atmosphere can be put to practical use.
Cost Reduction
District cooling has not only environmental advantages but also economic advantages: as with district heating centralized plants are particularly cost-effective and efficient compared to decentralized refrigeration systems. Initial investment in district cooling can pay for itself within a few years. This is especially true when one considers constantly rising energy prices. In the medium term lower operating costs and lower maintenance costs also bring economic advantages.
