Hot water cylinder for heat pumps

Heat pumps are becoming more popular in the UK due to the energy efficiency that they achieve for space heating and hot water heating systems, with a high coefficient of performance (COP) by free energy extraction from the air or ground and this is where a hot water cylinder for heat pumps comes into play for your hot water system and reduce running costs for your heating system.

But there is one main issue when utilising heat pumps to provide hot water to your property or commercial building, and that is the water temperature that can be produced and fed to the coil or coils of the heat pump cylinder as heat pump cylinders work with lower temperatures.

Hot water cylinders range specifically designed for heat pumps

But there is one main issue when utilising heat pumps to provide hot water to your property or commercial building, and that is the hot water temperature that can be produced and fed to the coil or coils of the hot water cylinders from your heating system.

Air source heat pump systems

Air source heat pumps are the most prevalent installation in the UK which extracts energy from the outside air as a renewable heating solution and reduce reliance on fossil fuels . A standard air-to-water heat pump can, on average, achieve a flow temperature between 55 and 60 degrees Celsius.

Although heat pump technology is developing at a fast pace and there are some high-temperature heat pump capacity models that can achieve 65° to 70°C water temperatures already on the market.

Air source heat pump and hot water cylinder installation diagram

Ground source heat pump systems

A geothermal or ground source heat pumps can reach a maximum temperature of 55 °C.

Heat pump hot water cylinders

Our heat pump hot water cylinders high performance coil has a large heat exchange surface area, maximising heat transfer while minimising pressure loss.

The heat pump cylinder for medium-sized to large heat pumps requires heat exchangers that can handle the higher flow rates brought on by the primary temperatures, which are usually 50 or 60 degrees Celsius for an air source heat pump.

This is the main reason an existing hot water cylinder has to be replaced with a suitable new heat pump cylinder that has been specifically designed for a heat pump system, is a large surface area coil to cope with the higher flow rates, and ensures good thermal energy transfer from the hot water tank into the domestic hot water to feed your baths, showers, and hot water taps of your hot water system.

Domestic hot water heat pump cylinders product specification

With a full range of cylinders for a heat pump installation, from 200 to 1,000 litres in our CV-HL range, which are vitreous enamel. The surface of the heat pump cylinders storage tank that comes into contact with water is protected by vitreous enamelling, a food-grade, impermeable lining that has a porcelain appearance,

Performance data for the enamelled heat pump cylinders

The output of domestic hot water is directly related to the water temperature feeding the heat exchanger (the coil) and the flow volume, as you can see from the following data chart:

For example, our 300 litre unit, when fed with water at 55 °C to the coil with a volume of 4 m3/hr, will produce 37 kW of output, which is 910 litres per hour when the DHW is raised from 10 °C to 45 °C.

CV-HL Performance data

These are detailed on the following brochure ( page 18 )

Enamelled heat pump cylinders brochure – Flexiheat UK

or our stainless steel heat pump cylinders option, which is designated the “GX” range. These are manufactured in 316L stainless steel, which is chemically pickled and passivated, giving the best corrosion resistance and life cycle costs for these water heaters. This range has better performance than our enamelled units.

Performance data for the stainless steel cylinder option

Stainless Steel versions

These stainless steel heat pump cylinders are detailed on the following brochure ( page 17 in particular)

Stainless Steel cylinders for domestic hot water production and storage brochure – Flexiheat UK

Our range benefits from:

Anti-Legionella Design:

Our high-efficiency coils are made to generate heat from the lowest point in these heat pump cylinders. This keeps there from being cold spots inside the tank where bacteria like Legionella could produce and grow.

Energy efficiency

With low heat loss due to our insulation which is rigid, mould-injected PU (CFC/HCFC-free, 0.025 W/mºK), they are rated either ErP “B” or “C” for heat loss according to the EU 812/2013 regulations and test standards, depending on the size of the cylinder.

Larger hot water heat pump cylinders

Domestic hot water tanks for heat pump use, from 1,500 to 6,000 litre capacity. With a detachable coils system for DHW production via an external energy source. They can be fitted with immersion electric elements or ceramic electric elements, as backup heating.

Our “SB” range with a twin coils heat exchanger.

SB range of larger capacity hot water heat pump cylinders

With side and top ND400 manholes to access the interior of the storage tank for inspection, cleaning, and maintenance tasks. Thermally insulated with rigid, mould-injected, 80 mm-thick, PU polyurethane foam, with insulated DN400mm side manhole.

DHW production figures and kW ratings for our SB range of calorifiers

The heat pump coils have large surface areas for optimal heat transfer, with low resistance, and are positioned within the heat pump cylinder to ensure low temperatures on the return circuit for ground source heat pumps or air source heat pumps.

With the largest range of heat pump cylinders on the UK market, please don’t hesitate to contact our sales team direct on 01202 822221, or  or click here for our email contact form.