Heating and hot water are among the biggest costs for many farms. While many poultry, pig and mushroom producers have switched to renewable sources such as biomass, there is a growing push for these farmers to explore heat pumps, which can be used in combination with solar energy.

Heat pumps essentially use similar technology to refrigerators to extract heat from the air, ground or water to provide space and water heating.

They can also provide cooling by running in reverse to remove heat from the building when it is hot.

Traditionally, heat pumps provided a low-temperature heat and were therefore best suited for low heat demand applications, such as well-insulated properties with underfloor heating, rather than conventional central heating systems that produce a much higher temperature output.

The advice has been that if a heat pump is used for water heating, it should be combined with another heat source to reach the necessary water temperature.

However, heat pump technology has improved significantly, with systems now available that can deliver water at temperatures exceeding 70°C creating new opportunities for farmers.

Types of heat pump

There are a number of different types of heat pump.

Air source heat pumps are the most common and need to be located outside in the open air.

They use a fan to draw air in, which flows over a heat exchanger containing a refrigerant liquid. An evaporator uses the latent heat from the air to heat the refrigerant liquid until it boils and turns into a gas.

This gas is then compressed, which causes it to increase in temperature. An additional heat exchanger removes the heat from the refrigerant (turning it back into a liquid), which can then be used as useful heat. Ground and water source heat pumps use heat trapped beneath the ground and in water bodies to boost the water temperature. This heat is then used to provide home heating or hot water.

Pros of the systems

Many pig production systems have already switched to heat pumps for providing space heating using air source systems. Most farmers prefer using air-to-water heat pumps, as they can be relatively simple to fit to houses using gas, biomass, or oil heating, even though they are less efficient and will require more maintenance than a ground source heat pump. If a farmer were to install a geothermal heat pump, there would likely be more groundworks required, which may add to cost and disruption on a busy farmyard. This, of course, depends on whether they opt for pipes in the ground or a borehole.

Insulation

Heat pumps are less forgiving than conventional heating systems when it comes to insulation. To ensure thermal efficiency, you need to minimise heat loss from system components (eg pipework, buffer tanks, heat exchangers, valves, and flanges).

A heat pump system for space heating works best in a well-insulated and airtight building, so some older housing units may require improvements to insulation before installation.

Savings

The Irish Farmers Journal recently attended the launch of Efficient Renewables’ new showroom in Newtowncunningham, Donegal. They supply a range of solar panels, heat pumps, and other energy equipment for the domestic, commercial and agricultural sectors.

Speaking to director Christy Lynch, he explained that heat pumps will save around 60-70% in energy costs compared to gas.

This saving increases significantly if powered by electricity produced from solar panels, also reducing heating emissions to nearly zero.

SSRH

While uptake has been low, the Support Scheme for Renewable Heat provides grants of up to 40% for air, ground and water heat pumps for commercial, industrial, agricultural, district heating, public sector, and other non-domestic heat users.

TAMS

Grant aid rates between 40-60% for air source heat pumps are available through TAMS, as well as for heat recovery units. The cost of these is calculated based on the rated capacity of the unit in kilowatts, valued at €801.92.

SEAI EXEED

The SEAI Excellence in Energy Efficient Design (EXEED) grant scheme is designed for public and private organisations planning an energy investment project. The grant aid is significant, up to €3,000,000 per project. Heat pumps are eligible, but likely as part of a larger energy efficiency upgrade project.

Accelerated Capital Allowance

While not a grant, the Accelerated Capital Allowance (ACA) is a tax incentive encouraging investment in energy-saving technology, including heat pumps. ACA allows a sole trader, farmer, or company that pays corporation tax in Ireland to deduct the full cost of the equipment from their profits in the year of purchase.