It does seem ironic that in a time when every effort is being made to reduce greenhouse gasses is critical to prevent further climate change, that the use of Heat Interface Units in apartments typically require almost twice as much energy to supply the hot water and heating needs of an apartment as compared to a gas boiler. Understandably after ‘recent events of fires in apartment/buildings, alternative heat sources such as HIU’s will become more the norm and specified.
It is equally ironic that those apartments installed with heat interface units suffer from overheating especially in the Summer months. Better insulation in buildings helps to save energy, but having an 80-degree primed Heat Interface Unit in a service cupboard will increase internal temperatures. Heat Interface Units are supplied for instantaneous hot water and hot water is required are 24/7 365 days a year.
Apart from the safety issue, it is difficult to understand why HIU’s are used. They are inefficient and create discomfort for the apartment users. A possibly explanation for poor efficiency and overheating could be the size of the Heat Interface Unit installed. Most manufacturers of HIU’s make a standard size unit for heating and hot water. This means when the heating load and hot water requirement is calculated by the designer, the choice of unit will be determined by the Hot water requirement. It is very unlikely that calculated load and the HIU load match. It is more than likely that the designer has already added an additional margin and sizing to the next unit automatically adds a further 10 to 20%. The HIU manufacturer states a flow rate requirement to meet its design duty. That flow rate could be significantly higher than the actual flow rate required. However, the system designed is not based on the actual design flow rate calculated by the designer but on the flow rate of the unit installed. The heat load of the actual apartment compared to the heat exchanger installed in the HIU could be significantly higher thus wasting energy and causing overheating.
A simple solution to reducing the energy loss in HIU and overheating is to manufacture a unit to the designs calculated by the designer. Using this approach to the installation of HIU, reduces the size of the heat exchanger and the requirement of the central boiler and pipework. HeatLink Technical Solution has always designed units to the designers requirements.