In this article, we aim to clarify the difference between two types of heat networks: 4th generation and ambient loop. For both, we’ll consider how they are affected by the Heat Network (Metering and Billing) Regulations, and how monitoring these types of heat networks can improve performance.

What is a 4th generation heat network?

Most heat networks in the UK have a very obvious heat generator, like boilers or large-scale heat pumps in the basement of a building or in a plant room on the site. Hot water is then pumped around the network, and each dwelling typically contains a Heat Interface Unit (or HIU) which transfers heat energy from the water arriving from the network (for 4th generation heat networks this is usually 55°C to 60°C) to the water or heating system in the home.  The lower temperature was introduced as a viable, and more cost-effective, transition away from fossil fuels to future heat supplies from local renewable and secondary sources such as industrial processes or underground transportation, and low-carbon fuels such as large biomass boilers or solar energy.

What is an ambient loop heat network?

An ambient temperature heat network works slightly differently. The system is essentially a two-stage heating design. A plant room heats water to around 15°C to 30°C (perhaps using waste heat from a data centre, or a river source heat pump, or some other source of low-grade heat), and then an individual heat pump in each home tops up this heat to a usable temperature for space heating or domestic hot water. So you’ve got a centralised heat generator as well as individual heat pumps in each dwelling, which makes use of thermal energy coming from the central plant.

At a glance:

Ambient Loop network 4th Generation heat network
Centralised source of heat? Yes Yes
Heat pump in each dwelling to top up heat from the central plant? Yes No
Heat Interface Unit (HIU) in the dwelling to transfer heat energy from the network to the dwelling? No Yes
Required to be metered by Heat Network (Metering and Billing) Regulations? Yes Yes
Temperature of water supplied to dwelling? 15°C to 30°C  55°C to 60°C

Learn more

We have written a white paper that you can download via the form below, and recently held a webinar to further delve into these differences also available to view below.

Where does Guru Systems fit in?

Guru Systems technology can be used to monitor ambient loop networks and 4th generation heat networks. Read more about our Guru Hub 2 and Guru Hub 3 Core, or speak to our sales team.

As well as the need to capture data to meet the requirements of the Heat Network (Metering and Billing) Regulations, in our experience, unmonitored heat networks do not perform well. Poorly performing networks cost more to run, and these costs invariably end up being passed on to residents.

Our heat network performance management platform Guru Pinpoint can be used to help ensure heat networks continue to perform as designed – whether it’s a 4th generation or an ambient loop heat network. Monitoring heat network performance is the easiest way to spot problems and inefficiencies when they first arise.

If you are interested in learning more, we have the following two CPDs available: ‘Capturing data from ambient loop networks’ and ‘Capturing and interpreting heat network performance data for designers and developers.’