Embassy of Denmark in the United Kingdom              HRSC0061

Embassy of Denmark in the United Kingdom

Air conditioning

 

The International Energy Agency estimated in 2018 that the growing use of air conditioners (ACs) in homes and offices would be one of the top drivers of electricity demand globally over the next 30 years, with an equivalent of ten new ACs to be sold every second up to 2050[6]. This trend looks likely to be mirrored in the UK.[7] A large degree of dependency on this single technology risks a vicious cycle whereby more ACs lead to higher energy consumption, leading to higher CO2 emissions, and increasing temperatures yet further. Additionally, ACs typically use refrigerant gases that are highly pollutant, having global warming potentials up to thousands of times that of CO2.[8]

There are less energy-intensive alternatives to AC use; for example, passive and low-energy cooling solutions such as solar protection devices, radiative cooling technologies, adequate ventilation, ceiling fans, evaporative cooling, nature-based solutions, urban greenery, or designing buildings to perform better under hot (and cold) conditions.

 


 

Good afternoon,

 

In regard to the three above questions, one of the most effective solutions to decarbonised cooling in the future will be cooling networks, otherwise known as heat networks or district heating and cooling.

Cooling networks use industrial chillers to cool water which is then transported via insulated pipes to homes and businesses. This technology has been used widely in Denmark, and is being used an increasing amount in UK heat network projects. Recent examples include the heating and cooling networks in the recently developed King’s Cross Coal Drops Yard and the redevelopment of Battersea Power Station. While these are relatively small examples, cooling networks could be scaled up to serve the vast majority of UK towns and cities. Copenhagen has 98% of buildings connected to heat networks, although not all of them also supply cooling.

Cooling networks bring many of the same benefits as heat pump-led heat networks. Large chillers are very efficient and can also use ambient sources of cooling, like river, sea, or ground water, to reduce the amount of energy required to cool buildings. Apart from being more energy efficient, this means that the heat removed from buildings will not contribute to increasing the air temperature in cities, which is a common circumstance in cities with large numbers of individual air conditioning units as the heat from inside the house is dispersed into the outside air, requiring the units to work harder and therefore consume more energy.


Embassy of Denmark in the United Kingdom              HRSC0061

As well as reducing energy consumption through efficiency, cooling networks can help to significantly reduce the need for both grid reinforcement and ‘peaking’ generation during hot or cold periods. This is because of the thermal mass of the water in the networks, the stochastic effects of a larger number of users (who will be cooling their buildings at different times), and networks ability to use thermal storage.

Thermal storage, both intra and inter-seasonal, helps to reduce the need for peaking and grid reinforcement, as well as reduce customers’ bills, by using energy to cool water at off-peak times, or when there is a large amount of renewable generation available, like very sunny and windy days. This hot or cool water can be efficiently stored for long periods of time, with some pit thermal storage maintaining above 90% efficiency over an entire year. You can therefore efficiently store heat in the summer, for use in the winter, or vice versa, much more efficiently than electrical storage through batteries. Onsite electrical generation for networks can further reduce the impact on the grid.

Heat networks also help avoid the significant upfront costs of heat pumps for consumers. As large infrastructure projects, they are able to attract both Government and private capital, and to spread the cost over a number of years. This is also true when cooling networks are compared to individual air conditioning units.

The UK’s public and private housing stock will require significant retrofit in order to decarbonise heating, in terms of heat generation, heat emitters, and energy efficiency measures. The same is true for cooling, although increased energy efficiency will make it easier to both heat and cool buildings. In areas that are likely to have a significant number of new heat networks, which are also likely to see a rise in cooling requirement during the summer, every effort should be made to include cooling in those networks where feasible.

Buildings will benefit both from the increased efficiency of networked cooling and the opportunity provided by the development and construction that will already be taking place.

The Government has made significant progress in expanding the UK heat networks sector in the Energy Bill, which is likely to see a considerable increase in construction when regulation and zoning powers come into place in 2025. This will also provide the opportunity for significantly more cooling through cooling networks and every effort should be made to take advantage of this for whole-system benefits.

Heating and cooling networks are a proven technology that is in use across Denmark, where they are helping to address a significant number of challenges from decarbonisation. As mentioned, they help to address the intermittency of renewable generation and avoid the need for expensive grid reinforcement. They also reduce the upfront capital costs of individual heating and cooling solutions and can help to keep ambient air temperatures lower through the use of ambient sources of cooling.

I would be very happy to discuss or expand upon any of the points in this submission. Kind regards,

Kieran Sinclair

 

August 2023