With a growing emphasis on sustainability, energy efficiency and renewable energy sources, the adoption of heat pumps is gaining momentum in both domestic and commercial markets.
But what exactly are Heat Pumps?
You instantly think of cooling whenever you hear the term refrigeration, however, the process of refrigeration is to remove heat and put it somewhere else. For instance, your refrigerator at home removes heat from the food stored inside the fridge, the heat absorbed from the food is then rejected outside the fridge into your kitchen.
So, a “heat pump” is a general term for a refrigeration cycle operating in reverse, typically a heat pump system will absorb heat from outside and reject it into something such as a building, raising the temperature and keeping it warm.
Fun Fact: the theoretic lowest temperature is -273.15c (zero on the Kelvin scale), anything warmer than this contains heat that could potentially be absorbed and moved somewhere else using refrigerants.
Energy Efficiency of Heat Pumps
Heat pumps are renowned for their exceptional energy efficiency, particularly when compared to traditional heating systems like boilers. The distinguishing feature of a heat pump is its ability to produce more heat output than the energy it consumes. This efficiency is achieved by harnessing heat from the surrounding air or ground and transferring it into the building.
For instance, consider a scenario where a heat pump consumes 1kw of energy from the grid. Through its operation, it absorbs an additional 3kw of heat from the environment. In total, the heat pump delivers 4kw of heat energy into the building. This means that for every unit of electrical energy used, the heat pump produces four units of heat.
In contrast, a gas boiler would require 4kw of gas to generate 4kw of heat. However, due to inherent inefficiencies, only around 3.5 kw of heat would actually be delivered into the building.
Similarly, an electric heater would consume 4kw of electricity to produce 4kw of heat, but without the efficiency gains offered by a heat pump.
In essence, heat pumps offer a remarkable advantage in efficiency, generating more heat energy than the electrical energy they consume. Moreover, if the electricity used to power the heat pump originates from renewable sources such as solar panels, the system can effectively operate in a carbon-neutral manner, further enhancing its environmental and sustainability capabilities.
Types of Heat Pumps
There are several types of heat pumps, including:
- Air To Air Heat Pumps (air conditioning, split systems, VRF systems) – These systems are typically more efficient than other heat pump systems because they only need to transfer heat once, directly from the outside air to the inside air. They respond quickly to adjustments in internal temperature settings and adapt rapidly to changes in external conditions. Additionally, they offer the advantage of providing cooling during the summer months.
- Air To Water Heat Pumps (monobloc or split systems) – These systems are among the most known type of heat pumps, favoured in the domestic market for their resemblance to traditional gas or oil boilers. These pumps are available in two main configurations: the monobloc unit, where the refrigerant circuit is housed entirely within one box and only the water piping runs between the heat pump and the source, and the split system, which involves refrigerant piping between the outdoor and indoor units to transfer heat directly into the water. Traditional radiators used with these systems must be larger than those used with gas boilers due to the lower flow temperatures, which typically range from 35°C to 55°C, making them especially well-suited for underfloor heating systems.
- Ground Source Heat Pumps (GSHPs) – also known as geothermal heat pumps, are a type of heat pump system that extracts heat from the ground to provide heating and cooling as well as hot water. Ground source heat pumps operate by absorbing heat from the ground through a circulating water solution, such as brine or glycol, within the pipes. In the UK, the temperature approximately 1 meter below the ground remains relatively stable throughout the year, irrespective of the air temperature and weather conditions above ground. This consistency allows the heat pump to operate under stable conditions year-round, enabling the system’s design to be optimised for these conditions.
- Open Loop Water Source Heat Pumps (WSHPs) – these are a type of systems operate similarly to ground source systems but involve circulating water that is directly extracted and pumped back from large bodies of water such as tanks, lakes, rivers, reservoirs, natural aquifers, or flooded disused mines, rather than a closed loop. This method of using naturally occurring water for heat extraction may require obtaining an abstraction and/or disposal license from the Environment Agency, and the water quality might require treatment and filtration to ensure safety. These systems typically do not require defrost cycles because they do not experience frosting like air source systems, thus avoiding periods without heat delivery. Additionally, their energy efficiency is sustained even in colder outdoor temperatures.
Here’s how they work
A heat pump operates on the principle of transferring heat from one place to another using a refrigeration cycle. The four key components are an evaporator, compressor, condenser, and expansion valve. In heating mode, the heat pump absorbs heat from an external source (like outside air or the ground), using the evaporator, and the refrigerant inside evaporates into a gas. This gas is then compressed, increasing its temperature, and transferred to the condenser, where it releases heat to the inside of a building as it condenses back into a liquid. The expansion valve reduces the refrigerant's pressure and temperature, allowing the cycle to start over. In cooling mode, the process is reversed, extracting heat from inside the building and releasing it outside. The system's efficiency lies in its ability to move heat rather than generate it, making it an energy-efficient solution for both heating and cooling.
- Evaporator: Accepts heat from the source (usually outside) to boil liquid refrigerant back into a gas at low temperature in the low-pressure side of the circuit created by suction from the compressor
- Compressor: Raises the pressure and therefore the temperature of refrigerant vapour and circulates refrigerant around the system.
- Condenser: Releases heat from the hot refrigerant in high pressure side of the circuit (usually a heat exchanger) which condenses it back into a liquid.
- Expansion valve/metering device: Regulates the liquid refrigerant flow into the evaporator and maintains a pressure difference between the condenser (high pressure) and evaporator (low pressure).
Your Legal Obligations Under The F-Gas Regulations
Your legal obligations under the F-Gas Regulations are crucial to ensuring the safe and compliant operation of heat pumps containing HFC refrigerants. These regulations set out specific requirements for the installation, maintenance and servicing of such systems, aimed at reducing environmental impact and promoting safety.
Here’s what you need to know:
Qualified Engineers:
As heat pumps contain refrigerant, they fall under F-Gas Regulations. Installation work involving refrigerants such as split type systems, needs to be carried out by a refrigerant qualified engineer, working for a certified company.
Service works that breach any refrigerant circuit needs to be carried out by a refrigerant qualified engineer, working for a certified company. This ensures that individuals working on these systems possess the necessary skills and knowledge to do so safely and effectively.
Certified Companies:
The company employing engineers must be certified by one of three approved bodies – REFCOM, Quidos or Bureau Veritas. This certification verifies that the company meets the required standards for handling F-Gas refrigerants and ensures compliance with regulatory requirements.
Indirect Refrigerant Leak Checks:
This also means that subject to the amount and type of refrigerant installed an annual refrigerant leak check could be required, this also needs to be carried out by a refrigerant qualified engineer working for a certified company.
All refrigerants have a GWP rating (global warming potential), a GWP rating of 1 means if released to atmosphere, the refrigerant would cause the same damage as 1kg of C02
The refrigerant leak check requirement starts when the volume of refrigerant multiplied by its GWP is 5000kg (5 tonnes) or more, this is called CO2/te (CO2 Tonnes equivalent)
It’s a legal requirement for manufactures to display the amount and type of refrigerant in their systems, this can typically be found on the data plate attached to the outdoor heat pump unit.
Monobloc systems where all the refrigerant components are hermetically sealed and contained within a single box (no interconnecting refrigerant pipe work) has a different rule, there’s no maximum period of time between indirect refrigerant leak checks on hermetically sealed refrigeration and air conditioning systems unless they contain F gas equivalent to 10 tonnes of carbon dioxide.
By adhering to these legal obligations, you can ensure the proper management and maintenance of heat pump systems containing HFC refrigerants, contributing to environmental protection and regulatory compliance.
For further information and guidance on the F-Gas regulations, please refer to our dedicated section on this topic.
Can We Help?
Heat pumps offer a sustainable and energy-efficient approach to heating and cooling, leading to decreased energy usage, minimised carbon footprints and enhanced indoor comfort. At Mattair, we possess the expertise and technical know-how to guide you through the various heat pump options, ensuring the selection of the perfect solution for your business needs. Call us today on 01246 414922 or email [email protected] and allow us to assist you in making the right choice.
Watch Now
Our Technical Sales Director, Ian Fisher, has recently recorded a series of webinars on heat pumps as part of the Institute of Refrigeration’s masterclass series – Click here for valuable insights and detailed information:
Webinar 1: What are Heat Pumps & Heat Pump Types
Webinar 2: How Heat Pumps work – taking a look at the connection between the vapour compression cycle and the water cycle.
Webinar 3: Case Study – A refrigeration engineer servicing a domestic heat pump and how involved was the process:
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