The heat supply for Swedish multi-family residential buildings is becoming more complex, and today it is fairly common to combine district heating with a second heat source. The most common heat source to combine with district heating in Sweden is an exhaust air heat pump. On average, the exhaust air heat pump covers 31% of the yearly heat load and is given full load priority. There is a missed potential in cost and CO2 savings when one heat source is given full load priority, since marginal production costs and CO2 emissions constantly vary in both the electrical grid and the district heating system. The aim of this study is to evaluate how buildings with several heat sources should be operated using hourly energy prices. Hourly heat and electricity prices for Gothenburg have been established for two years based on the marginal costs of heat and electricity generation. These prices have been used to evaluate the most common combinations of heat sources. Results show that the most common combination with an exhaust air heat pump with full load priority does not lower costs compared to the reference case with only district heating. However, having a control system that allows heat source shifting and gives load priority to the heat source with the lowest cost each hour can greatly reduce the heating cost, and systems with larger heat pumps show even greater potential for heat source shifting.
[1]
Jan-Olof Dalenbäck,et al.
Potential of residential buildings as thermal energy storage in district heating systems – Results from a pilot test
,
2015
.
[2]
Tim Johansson,et al.
Energy performance certificates and 3-dimensional city models as a means to reach national targets A case study of the city of Kiruna
,
2016
.
[3]
Paul Davidsson,et al.
Deployment of Agent Based Load Control in District Heating Systems
,
2010,
AAMAS 2010.
[4]
Holger Wallbaum,et al.
Handling data uncertainties when using Swedish energy performance certificate data to describe energy usage in the building stock
,
2015
.
[5]
Manfred Morari,et al.
Use of model predictive control and weather forecasts for energy efficient building climate control
,
2012
.
[6]
Jarek Kurnitski,et al.
Heating system return temperature effect on heat pump performance
,
2015
.
[7]
Johan Kensby.
Buildings as thermal energy storage – Pilot test and large-scale implementation for district heating systems
,
2015
.