What is ground source cooling?

Hot summers are becoming more and more common, and the need for cooling is increasing even in northern climates. At the same time, minimising energy consumption and environmental impact is more important than ever.

For users of ground source heating, ground source cooling offers an extremely energy-efficient way to cool a property. By utilising the naturally low temperature of the ground, cooling can be provided with very low operating costs and without the need for traditional compressor-driven cooling equipment.

The circulating brine in the energy well is naturally cooled by the stable temperature of the surrounding ground. A circulation pump transfers the cooling energy to a fan coil unit, where the heat exchanger cools the indoor air. The cooled air is then distributed throughout the property.

In addition to its low operating costs, ground source cooling is also an environmentally friendly solution. In the latest Gebwell G-Eco ground source heat pumps, the natural R290 refrigerant and ground source cooling form a combination that supports both high energy efficiency and low emissions. The solution is also a future-proof choice in light of evolving environmental regulations.

Ground source cooling is commonly referred to as passive cooling, as it utilises the naturally low temperature of the ground without the use of a compressor. In addition to an energy well, only a circulation pump and a distribution system, such as a fan coil unit or cooling coil integrated into the ventilation system, are required.

Ground source cooling can also be utilised in industrial and commercial properties. Particularly in larger projects, cooling improves the overall profitability of a ground source heat pump system and further shortens the payback period.

Effortless and cost-effective ground source cooling

Ground source cooling is highly cost-effective, with more than 95–98% of the cooling energy coming directly from the ground. Electricity is only required for operating the circulation pump and the fan coil unit.

Ground source cooling also eliminates the noise associated with conventional chillers and frees up valuable technical space for other uses. Without separate cooling units, there is also less maintenance and servicing required.

With ground source cooling, there is no need to worry that savings achieved through efficient heating will be offset by cooling costs during the summer. The operating costs are only a fraction of those associated with conventional cooling systems. A power input of just a few tens of watts can provide several kilowatts of cooling capacity.

The energy consumption of ground source cooling is comparable to that of a single incandescent light bulb. Its efficiency is therefore in a class of its own.

An additional benefit is that excess heat removed from the building is transferred back into the ground. In other words, the more cooling is used during summer, the more thermal energy is stored for the following heating season.

Distribution of ground source cooling within a property

Ground source cooling can be distributed through the ventilation system, fan coil units, radiant panels or underfloor pipework.

Cooling via the ventilation system can be implemented through a heat recovery unit or a dedicated cooling coil. This solution is particularly worth considering in new-build projects, where cooling requirements can be taken into account during the design phase.

A fan coil unit consists of a heat exchanger and a fan that circulates room air through the exchanger. Fan coil units can be installed on a wall or ceiling and provide efficient room-by-room cooling.

Cooling can also be distributed through underfloor heating pipework as underfloor cooling. This enables comfortable and even cooling throughout the building. When using underfloor cooling, wet areas should ideally be separated from living areas into dedicated circuits, allowing bathrooms and utility rooms to remain comfortably warm while other spaces are cooled.

All Gebwell ground source heat pumps are factory-equipped with cooling control readiness, making the implementation of ground source cooling straightforward. Cooling can also be retrofitted to existing systems, although installation is easiest when carried out alongside the original heat pump installation.

What types of properties is ground source cooling suitable for?

Ground source cooling is a versatile and highly cost-effective solution suitable for a wide range of properties:

• Detached houses with an energy well and underfloor heating.
• New-build properties, where cooling requirements can be considered during the design phase, particularly within the ventilation system.
• Apartment buildings undergoing renovation, where cooling can be distributed through dedicated fan coil units.
• Properties with ground or water-based collector loops, such as lakeside properties. Cooling can also be achieved through these energy sources if the collector system is sufficiently large.
• Large properties, including schools, office buildings, apartment buildings and industrial facilities. In many cases, ground source cooling can significantly reduce or even eliminate the need for conventional mechanical cooling.

Examples of Gebwell references utilising ground source cooling

Ground source cooling has been successfully implemented alongside ground source heating in a wide range of Gebwell projects, including:

• KONE Oyj headquarters in Munkkiniemi
• A semi-detached house in Tampere using underfloor cooling
• Jospak Oy, where both passive and active cooling are utilised alongside ground source heating