Heat Interface Units are usually installed with heat meters, giving both flat owners and occupiers the advantage of being able to control their heating use and have precise information about the amount of heat used, hence the right billing.
HIUs evolve technologically and we have recently noted the uptake of units that provide both heating and cooling or just cooling. Sales of these units are currently limited, but they are expected to gain share in the future, as they offer some very specific advantages.
There is also a growing market for Fresh Water Modules (FWM), i.e. HIUs supplying domestic hot water only.
Heat interface units are installed with either centralized heating systems or in dwellings that draw heat from district heating networks to feed individual buildings and dwellings.
District heating and cooling networks have witnessed significant growth in many European countries and in China in the last five years.
Heat networks benefit from decreasing capital costs and show a trend towards lower distribution temperatures (~55oC) and increased efficiency. This trend is in line with the development of the concept of 5th generation heat networks, which do not have central energy centre and have distribution of water at, or close to, the ambient ground temperature, highly reduced heat losses, as well as distributed heat transfer in every building using local heat pumps for heating or cooling, based on the principle of recycling energy.
While installations of water- and ground-to-water heat pumps and the use of energy-from-waste are growing, industrial boilers and CHPs remain the main source of heating. For instance, 85% of planned heat networks in the UK, will have a CHP as primary source for heating and 50% will have a gas boiler as a backup. The remaining 15% will use geothermal, ground source or water source heat pumps.