Your guide to high temperature heat pumps

Most heat pumps operate at lower temperatures than traditional gas boilers. But that doesn’t have to be the case!

High temperature heat pumps offer a way to provide space heating and hot water at temperatures much closer to what buildings are typically set up for, which comes with a whole host of benefits. Here’s all you need to know.

What is a high temperature heat pump?

High temperature heat pumps work in much the same way as standard heat pumps.

In other words, they absorb warmth from sources such as the air or ground before converting it to higher temperatures – enabling them to heat buildings in a way that feels pretty similar to a standard gas boiler.

However, most heat pumps operate at much lower temperatures than the traditional boilers most of us are used to. Most gas boilers are set up to operate at 80C with a 60C return temperature. Meanwhile, most standard heat pumps will only reach between 44C and 55C.

This doesn’t mean that they’re ineffective at heating your building – far from it. Rather, it means retrofitting larger emitters (by which we mostly mean radiators or underfloor heating), pipes, pumps and valves etc. to create the same effect.

On the other hand, a high temperature heat pump operates at temperatures much closer to those that are used for standard gas boilers.

Not only does this make them more effective at providing domestic hot water, but it also makes them easier to retrofit (depending on the refrigerant), as fewer changes need to be made to a building’s existing infrastructure.

They achieve all this without sacrificing efficiency. In fact, high temperature heat pumps are usually just as efficient as low temperature heat pumps and much more efficient than traditional gas boilers – reaching up to 400% efficiency!

How do high temperature heat pumps work?

There’s no one way to create a high temperature heat pump.

Instead, creating a heat pump that operates at high temperatures can be achieved in a few different ways.

Here are some of the approaches that we take here at Clade.

Natural refrigerants

Refrigerants are integral to the functioning of heat pumps.

As these fluids absorb heat, they boil and turn into gas. They then condense back into fluids as they release heat, in a process known as the vapour compression cycle.

Different refrigerants evaporate at different temperatures, making choosing the best refrigerant essential when it comes to developing a high temperature heat pump.

At Clade, our high temperature heat pumps contain either CO2 (carbon dioxide) or R290 (propane) – both of which are natural refrigerants.

CO2

CO2 heat pumps are suitable for high temperature requirements.

They’ve proven themselves at over 100°C and have repeatedly shown that they can consistently produce a hot water supply at 80°C – even with variable ambient conditions.

The Acer is our flagship CO2 heat pump here at Clade. It delivers high temperatures of 70 to 80 degrees, while benefiting from the high performance associated with CO2.

Not only is this refrigerant efficient at high temperatures, but it also has the lowest global warming potential (GWP) of all refrigerants at just 1.

Better still, it’s non-toxic and non-flammable, meaning it’s classified as a safety group A1 refrigerant and can be used safely in public locations like supermarkets.

R290

R290 refrigerant gas is another fantastic option for high temperature heat pumps.

At Clade, we’ve recently developed a groundbreaking high temperature R290 heat pump – the Birch HT – that operates at 80C flow with a 10C temperature differential (that’s the difference between the flow and return temperatures).

This is as close to traditional boiler temperatures as it’s possible to get with a heat pump – which makes retrofitting these heat pumps super easy.

They act as a direct replacement for traditional boilers, without requiring any modifications to the building.

Similarly to CO2, R290 is highly efficient and non-toxic, offering a low GWP of just 3 (or less depending on the time considered).

However, it’s often favoured over CO2 for retrofitting, as it requires conditions that are more similar to what the industry is used to.

Cascade systems

Cascade systems offer another way to create a high temperature heat pump.

These heat pumps use two cycles with two different refrigerants – one low temperature and one high temperature.

In the first, the refrigerant evaporates at a very low temperature and condenses in the heat exchanger at relatively low pressure and temperature.

This enables heat to move to the evaporator, which causes the second refrigerant to evaporate too. This refrigerant also condenses at a relatively low pressure, keeping the heat output high.

At Clade, our cascade heat pump – the Larch – combines an R290 air source heat pump and R600a water source heat pump to offer flow and return temperatures that closely match those of traditional boiler systems, at 82⁰C / 71⁰C.

The specifically designed pair of low temperature and high temperature heat pumps work in harmony for maximum efficiency, allowing each working fluid to work at optimal conditions.

What are the pros and cons of high temp heat pumps?

Umming and ahhing about whether a high temp heat pump is worth it? Here are some of the main pros and cons to help you decide.

Pros

• Retrofitting: High temperature R290 heat pumps are easy to retrofit, as you won’t have to make any changes to your building’s existing infrastructure.

• Insulation: High temperature heat pumps are a good option for buildings that can’t easily be better insulated or have a new heating system fitted such as a large hospital.

• DHW: High temp heat pumps are particularly effective at providing domestic hot water.

• Eco-friendly: High temp heat pumps are renewable and Clade’s use of natural refrigerants makes them an eco-friendly choice.

Cons

• Cost: High temp heat pumps tend to cost more than regular heat pumps (although you may save money overall by reducing your retrofitting costs).

• Running costs: Running a heat pump at higher temperatures can cost more than running one at lower temperatures.

• Weight: High temp heat pumps are often heavier than standard heat pumps.

Is my building suitable for a high temp heat pump?

Most buildings are suitable for a high temperature heat pump.

But there are some buildings that could particularly benefit from one, including:

• Listed buildings or those in a Conservation Area
• Buildings that are difficult to retrofit
• Business premises that need to continue operating during installation
• Buildings that face extreme weather conditions and temperatures
• Those that need one solution for space heating and hot water

Not sure if your building is suitable for a high temp heat pump? Our team of experts would be happy to scope out your project and help you decide on the best course of action. Which brings us onto…

Let us help you with a high temperature heat pump

A high temp heat pump could be right up your street if you’re hoping to decarbonise without having to make extensive modifications to your existing building.

Our Birch HT heat pump is designed to be a direct replacement to your existing gas boiler.

Simply swap them out and you won’t even have to replace your radiators. All while benefiting from R290 refrigerant, which is low GWP and non-toxic.

It’s a no-brainer for both your business and the planet.

Simply get in touch with our team of experts to learn more.