Heat interface unit
The BSRIA guide to heat interface units BG 62/2105 defines heat interface units (HIU sometimes referred to as ‘heat boxes’) as ‘…the means of connection of the consumer’s heating and hot water systems to a heat network and may include isolation and control valves, heat exchangers, pumps and metering devices.’
Traditionally in the UK, individual properties have been provided with their own heating systems, typically a boiler, providing domestic hot water (DHW) and central heating (CH). District heating provides heating to a group of buildings from central thermal energy generation plant via a network of fluid distribution pipes. It is widely used for residential, commercial, local authority, government, and industrial buildings as well as for universities and hospitals where there are a variety of discrete buildings located around a campus.
As greater attention has been paid to energy consumption and carbon emissions, so there is increasing interest in the use of district heat networks as a means of supplying heat more efficiently, particularly in multi-storey developments, where alternative, individual low-carbon technologies may be more difficult to install.
Modern district heating systems generally use pressurised hot water for transferring heat from the central plant. Combined heat and power systems (CHP and sometimes called cogeneration), or other low-carbon technologies can be used for the central heat supply plant. CHP involves the local generation of electricity with the waste heat from the generation process being recovered and used in building heating systems or industrial processes. CHP is very energy efficient compared with traditional local generation of heat and import of electricity from large centrally-located electricity generation stations.
Heat interface units allow connection to a centralised heat network whilst still giving individual occupants control over the temperature in their property and allows individual metering and billing. They can provide heating only, or can provide heating and domestic hot water. BSRIA Guide BG 62/2105 suggests that installing a HIU linked to a heat network rather than a conventional boiler can have significant economic and environmental benefits, but that successful operation depends on appropriate system design and specification, and competent installation and maintenance.
There are a number of potential advantages to heat interface units:
- Central heat generation can be more efficient than local generation.
- It can be easier to integrate low carbon technologies.
- As local boilers are not required, there is no gas distribution network or flue requirement. This can result in both capital an operational cost savings.
- HIU’s can be installed outside of individual properties, giving easy access for landlords.
- They can allow remote monitoring and metering of consumption.
- They may allow a higher flow rate than domestic combination boilers.
Multi-zone systems may be provided for larger properties, and some systems may include a hot water cylinder. Typically, domestic how water supply is provided at around 75°C, and so if lower temperature water is required for a heating system such as underfloor heating , a mixing valve may be required. There may be hydraulic separation between the distribution network and the property, where distribution pressures may be high (such as in tall buildings) or to reduce the potential impact of leaks.
[edit] Related articles on Designing Buildings Wiki
- A technical guide to district heating (FB 72).
- Allowable solutions.
- Big growth in district heating markets - now and on the horizon.
- Biomass boiler.
- BSRIA guide to heat interface units
- CHP boiler.
- Combined heat and power.
- District energy networks
- Geothermal energy.
- Heat exchanger.
- Heat Networks Investment Project HNIP.
- Heat pump.
- Heat sharing network.
- Heat source.
- Types of domestic boiler.
Featured articles and news
IHBC share news on the Social Housing Retrofit Accelerator
To support in Social Housing Decarbonisation Fund bids
A change to adoptive architecture.
A must read for all built environment professionals.
A sun, tide, mass or scratch dial.
A brief description of time in the sun.
ICE Trustee Board update June 2022
Given by ICE President Ed McCann.
Artificial intelligence and project management
Two new research reports published by APM.
Association for Project Management membership offer
50% off APM Associate membership for Designing Buildings users.
Building safety, a shifting landscape for professionals
A commentary from the insurance perspective.
In brief with further links.
Walter Segal: self-built architect
A definitive book on a pioneer of green architecture.
Funding for heritage on the high street
Using heritage as a catalyst for reviving historic centres.
Commonwealth Heads of Government Meeting update.
Declaration prioritising sustainable urbanisation adopted.
A small hidden, often distant but key building component.
Some brief words about the actuator.
CIAT Chief Executive steps down.
After 34 years at the Institute.
Volunteer opportunity launched by the ICE
To support the next generation of engineers.
Provisional findings show illegal cartels in the industry.
CIAT reporting from the Competition and Markets Authority.
Making sustainable construction number one priority.
The future of construction report.
Interview with ECA CEO.
Many provisions came into force on June 28, 2022.
With room to expand.
An information packed session at the BSRIA conference.
Refurbishment, Energy Efficiency, Indoor air and process.
Create a profile, write informed product articles and share.
Aluminium Composite Panels (ACP) is one example.
We are indeed now 10 years old, so go on and be bold !
Write about something you know, help us build and grow !