The Danish district heating company HTF is in the process of establishing district cooling in Høje Taastrup, in Greater Copenhagen, Denmark. Powered mainly by heat pumps, the system will ensure low-cost heating while providing energy efficient, affordable and low-carbon district cooling at the same time.
Ramboll has developed the business plan and project proposal, and mapped out potential supply areas. Currently, Ramboll is working on the technical designs to be used during the tendering of the heat pumps and thermal storage systems.
A new network of pipelines
In essence, district cooling is the distribution of cold water to buildings in need of cooling. During the feasibility study and mapping of potential supply areas, Ramboll identified several buildings with great need for cooling.
- The project involves building a network of pipelines, where you construct only parts at a time. Not all buildings are ready to be connected to a district cooling network so it will be an ongoing process to build up this climate-friendly and long-term energy solution, says Peter Kaarup Olsen, Senior Consultant at Ramboll’s Energy division.
Cooling for fruit, vegetables and flowers
Ramboll developed the business plan and project proposal for the southern part of the municipality by outlining the financial aspects and developing a fictitious district cooling system. The mapping was carried out in 2014 and identified great potential for district cooling.
“Especially in the southern part of Høje Taastrup, we have begun the development of the district cooling system. The system now includes ‘Copenhagen Markets’, where the district cooling plant has been put into operation. Covering an area of 67,000 m2 with ten metres from floor to ceiling, the roofed halls are home to the largest wholesale market for fruits, vegetables and flowers in Northern Europe”, says Peter Kaarup Olsen.
Socioeconomic and economic benefits
Ramboll has been involved in the project from the beginning. A feasibility study from 2014 showed significant socioeconomic and business economic benefits from establishing district cooling in the municipality of Høje Taastrup. By utilising surplus heat from heat pumps, HTF will both supply users with cooling and cut their annual energy consumption by 10-15%.
“Implementing district cooling has several societal benefits compared to the use of individual cooling plants. District cooling utilises significant amounts of surplus heat, lowers investment costs, enables use of wind energy, and creates a more flexible power consumption through co-generation of district heating and cooling”, says Peter Kaarup Olsen.
District cooling leads to increased efficiency
The project is financed through the sale of surplus heat to district heating consumers in the municipality and by utilising economies of scale.
“By installing few and centralised cooling plants rather than many decentralised ones, you use less energy overall because of increased efficiency. Moreover, you reduce the cost of investment, operation and maintenance. All in all, the amount of energy needed is reduced while efficiency is increased. The district cooling system leverages the synergies with district heating through co-generation and storage of heat and cold, which results in intelligent energy consumption”, says Peter Kaarup Olsen.
The combined use of district heating and cooling poses new challenges when the goal is to include all surplus heat in the system. In summer, when the consumption of cooling peaks, and heat consumption is at its lowest, the fluctuations in heat production make it difficult to store the surplus heat. To solve this challenge, HTF intends to establish a thermal storage system. Whether the storage system is to be divided into short-term and long-term is under consideration.
The storage system is expected to charge and discharge 50MW, both to VEK’s transmission district heating system and to HTF’s distribution system. The thermal storage system will receive district heating from VEK’s transmission system at approx. 95°C and return the heat back to either the return path of the transmission system or to the transmission channel of the transmission system via heat pump or electric heater.
The storage system will also be able to receive surplus heat from HTF’s distribution system – a surplus heat primary generated through district cooling. Furthermore, the thermal storage system is expected to receive heat from an external solar heating plant that is under construction.
With 30 years of experience in district heating and cooling, Ramboll offers a full range of services. Ramboll has served as an energy consultant for HTF for many years.