Integrating heat pumps into greenhouses can have several advantages and disadvantages. Mark Whorlow with Toyesi discusses some of the pros and cons of heat pumps. Toyesi has been helping customers right across Australia to understand how heat pumps can benefit their businesses. "Heat pumps offer numerous benefits for farmers and greenhouse owners, including significant energy savings, reduced environmental impact, and the ability to maintain optimal growing conditions. However, it is essential to consider the initial costs, climate dependency, and maintenance requirements when evaluating heat pumps as a heating and cooling solution", says Mark.

"Greenhouses and farms often have existing hydronic water loops powered by gas-based, oil, or similar boiler heaters. Depending on the circulating temperatures, most heat pumps can be connected to the existing system relatively easily. Power supply, plumbing, and storage tanks are required, and then you are off to continue your greenhouse heating. Circulating water under 45 degrees can be supported by most heat pumps, but temperatures over 45 will require specialty heat pumps", he starts when asked about the integrability of the equipment.

Energy efficiency & savings
Heat pumps are renowned for their exceptional energy efficiency. "They can produce more heating or cooling energy compared to the electricity they consume. This energy efficiency can result in substantial cost savings for farmers and greenhouse owners in the long run. In Australia, savings of up to 50 to 60% per year can be expected on town gas suppliers, and over 70% with bottled gas or other fuel-type boilers. If coupled with solar power and batteries, the running cost savings can almost reach 100%", Mark adds." And heat pumps operate using renewable energy sources, such as the heat extracted from the ground, water, or the surrounding air. By utilizing this renewable energy, heat pumps significantly reduce greenhouse gas emissions, contributing to a greener and more sustainable agricultural operation."

Depending on the greenhouse setup, heat pumps can offer both heating and cooling capabilities, making them suitable for year-round use in greenhouses, hydroponics, and other similar projects. Growers can easily regulate the temperature and maintain optimal growing conditions for their crops, regardless of external weather conditions. Some specialty heat pumps can heat one area while cooling another.

Improved crop health and yield
Maintaining stable and controlled temperatures within greenhouses is crucial for crop growth and productivity. "Heat pumps provide consistent heating or cooling, allowing farmers to create and maintain ideal growing conditions. This can result in healthier plants, faster growth rates, and increased crop yields. Some growers using accurate temperature control have been able to extend growing periods or even trick the plants into 2 growing seasons."

Reduced reliance on fossil fuels:
Traditional heating systems in agriculture often rely on fossil fuel combustion, such as oil or gas. "Heat pumps offer a clean alternative, reducing dependence on these non-renewable energy sources. Using solar in conjunction with heat pumps can lead to a reduced carbon footprint and contribute to a more sustainable agricultural sector", Mark says.

High initial costs
But there are also cons. "The high initial costs is the biggest stumbling block for most growers due to running constantly on tight budgets and strict cashflow issues. Heat pumps often have higher upfront costs compared to conventional heating systems due to equipment, installation, and setup expenses", says Mark. "These costs can be up to double to four times dearer than many farmers anticipate. However, it's important to consider the long-term cost savings and energy efficiency benefits. With typical payback periods from as low as 1 up to 5 years, depending on setup and use. Although adding more to the initial expense, adding solar panels to offset the grid electricity use, nearly all the ongoing power running costs can be reduced to nearly zero. You will find that you either invest today or continue to keep paying tomorrow."

Climate dependency:
Heat pumps' performance can be affected by external temperatures. In colder climates, heat pumps may lose efficiency and struggle to provide sufficient heating during extreme cold spells. "Additional heating solutions or backup systems may be necessary in such cases. Sizing the heat pump correctly for peak use requirements at worst-case ambient conditions can alleviate most if not all this concern. However, it will increase equipment size", Mark explains.

Geothermal heat pumps can also alleviate some of the climate fluctuations concerns. However, geothermal initial setup can be double or more than the standard heat pump setup cost. "Thus, geothermal is usually only considered in areas that drop below zero consistently for extended periods. Hence why they are popular in Europe, but less so in Australia."

Maintenance and repairs
Heat pumps require regular maintenance to ensure optimal efficiency and effectiveness. "Filters, coils, and fans must be inspected, cleaned, or replaced periodically. In case of malfunctions or breakdowns, repairs could be more costly and time-consuming compared to conventional heating systems. Preventative maintenance and regular service up to 4 times a year is advisable to keep the equipment as efficient as possible."

Noise levels
Heat pumps emit a certain level of operational noise, which may be a concern for farmers or greenhouse operators located in residential areas. "Noise reduction measures, such as locating the heat pump away from living spaces or implementing sound barriers and sound attenuation, may be necessary to address this issue."

Reduced reliance on fossil fuels
Traditional heating systems in agriculture often rely on fossil fuel combustion, such as oil or gas. "Heat pumps offer a clean alternative, reducing dependence on these non-renewable energy sources. Using heat pumps can lead to reduced carbon footprint and contribute to a more sustainable agricultural sector", Mark concludes.

For more information:
Mark Whorlow, General Manager Sales & Marketing
2/27 Binney Road, Kings Park, NSW 2148
Tel.: (61 2) 9679 9400
Mob.:(61 4) 21 386 320
Fax: (61 2) 9679 9402