Two-port (variable flow) control strategy
Heat Interface Units (BG 62/2015) was written by Reginald Brown and published by BSRIA in December 2015. It states: ‘In two-port control, a two-port control valve varies the flow of water through the heat emitter in order to vary the heat output. A typical example of a two-port control valve is the thermostatic radiator valve. In order to achieve good control, the pressure differential across the valve should be relatively constant. This is achieved by utilising a variable speed circulation pump with pressure control. If a constant speed pump is used then the pressure differential increases as the valve closes, resulting in poorer control and waste of pump energy. The benefit of two-port control for the heat emitters associated with heat networks is that it minimises the return temperature.’
--BSRIA
[edit] Related articles on Designing Buildings
- A technical guide to district heating (FB 72).
- Big growth in district heating markets - now and on the horizon.
- BSRIA articles.
- BSRIA definitions.
- BSRIA guide to heat interface units.
- Communal heating.
- Direct heat interface unit.
- District energy networks
- Domestic micro-generation.
- Heat interface unit.
- Indirect heat interface unit.
Featured articles and news
The first line of defence against rain, wind and snow.
Building Safety recap January, 2026
What we missed at the end of last year, and at the start of this...
National Apprenticeship Week 2026, 9-15 Feb
Shining a light on the positive impacts for businesses, their apprentices and the wider economy alike.
Applications and benefits of acoustic flooring
From commercial to retail.
From solid to sprung and ribbed to raised.
Strengthening industry collaboration in Hong Kong
Hong Kong Institute of Construction and The Chartered Institute of Building sign Memorandum of Understanding.
A detailed description from the experts at Cornish Lime.
IHBC planning for growth with corporate plan development
Grow with the Institute by volunteering and CP25 consultation.
Connecting ambition and action for designers and specifiers.
Electrical skills gap deepens as apprenticeship starts fall despite surging demand says ECA.
Built environment bodies deepen joint action on EDI
B.E.Inclusive initiative agree next phase of joint equity, diversity and inclusion (EDI) action plan.
Recognising culture as key to sustainable economic growth
Creative UK Provocation paper: Culture as Growth Infrastructure.
Futurebuild and UK Construction Week London Unite
Creating the UK’s Built Environment Super Event and over 25 other key partnerships.
Welsh and Scottish 2026 elections
Manifestos for the built environment for upcoming same May day elections.
Advancing BIM education with a competency framework
“We don’t need people who can just draw in 3D. We need people who can think in data.”