Analysis of the heat pump for heating with remote heating return
The goal of the project is to analyze the possibility and the potential for interaction between district heating and electricity sector, using individual heat pumps for heating with remote heating return. New consumers or small communities that connect to the collective heat supply, can thus use the return heat. The technology, which utilizes the interaction between district heating and electricity sector, in the form of shuttle heat and heat pumps can thus lead to:
- The loss in transmission and distribution line is reduced
- The return temperature to the power plant is lowered
- Better utilization of the heat produced
- Improving the plant's efficiency and
- Enhance the implementation of electricity in the district heating sector
Is to examine the situations in which it is advantageous to connect new consumers, by using the return temperature. This is done by verifying the theoretical calculations with measurement data. The project analyzes thus a technology which can result in a smooth transition for heat supply with low-temperature heating. The project established a service line from the return heat to supply a larger dwelling, as oil previously used. Here installed a heat pump, which will cover the need for heating and hot water. Return heat is used simultaneously for heating a workshop with radiant heat. It allows both to verify the calculations of the heat pump with return heat and the use of recycled heat directly to the heating, which can be relevant in low-energy houses. Work packages, which has several phases, is; Analysis and development, implementation and verification and communication.
Heat pumps as source for return heating in district heating are a good and competitive solution under the right circumstances. The potential for using this technology now and in the future is bright. Heat pumps combined with return heating is competitive against alternative solutions at certain costumers, especially large consumers close to transmission cables and consumers not able to establish geothermal heating. And an advantage for this solution is that it can heat the building all year.
Most district heating companies in Denmark cannot earn money on the sale of district heating. The advantage of lower temperatures of the return water and the costs related to heating of the return is compared and the price of the return water can be calculated. The advantage by cooler return water is if the heating plant is condensing. If it’s not the advantage is smaller. The annual cost for heating supply by heat pumps on the return is based on the costs for heating supply compared with conventional district heating.
The increasing amount of electricity from wind turbines can with advantage be used for improving the district heating system. With a COP at 5, the electricity consumption for heating for a standard home is 20 % of the total energy consumption for heating. The higher COP’s, the bigger amount of electricity consumption will be for heating.
The value of the return heat will vary from plant to plant related to the production and capacity. If the primary production system consists of motor-driven system with a condensing boiler or a solar heating system, cooler return water has a higher value due to improved production efficiency by lower water temperatures.
Experiences from this project can together with suitable technologies deliver alternative solutions for electricity overflow. The technology can with advantage for consumers, heating plant and society used for heating of new consumers.
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| Næstved Varmeværk a.m.b.a. | ||
| DANSK VARMEPUMPE INDUSTRI A/S | ||
| Aars Fjernvarme a.m.b.a. | ||
| Oksbøl Varmeværk a.m.b.a. | ||
| Skanderborg-Hørning Fjernvarme | ||
| Odder Varmeværk a.m.b.a. |
