Robert Haberl

A unified model for the simulation of oil, gas and biomass space heating boilers for energy estimating purposes. Part II: Parameterization and comparison with measurements

A semi-physical model for the simulation of oil, gas and biomass space heating boilers has been parameterized based on measurements on nine different boiler units and simulation results have been compared to results obtained from measurements in steady state and transient operation. Although the agreement between simulated and measured boiler efficiencies was within the range of measurement uncertainties in most cases, model improvements are expected to be possible concerning the heat capacitance modelling in cycling on/off operation as well as influences of start and stop behaviour on the overall efficiency. It is found that electricity consumption during cycling on/off operation of small pellets or oil space heating boilers may have a significant influence on the overall energy balance of these units. This influence increases strongly with decreasing heat load and increasing number of on/off cycles.

Towards an Harmonized Whole System Test Method for Combined Renewable Heating Systems for Houses

The objective of this work is the development of harmonized efficiency test methods for combined renewable heating systems for houses, using a hardware-in-the-loop approach. An overview of the principles of the existing whole system test methods used by 3 research institutes involved in the project (MacSheep 2012) is given. Main objectives are realistic dynamic test sequence elaboration for solar and heat pump systems and comparison of results from tests achieved in different institutes. In order to reach these objectives, the first phase of the work aimed to harmonize the boundary conditions that comprise both the physical boundaries of the tested system as well as the climate and heat load definition, and this is presented in the first part of the article. The second part presents two methodologies to elaborate 12-days and 6-days whole system test sequences, validation results for solar and air source heat pump systems (SHP) and a methodology for achieving equal amount of space heat supplied by the tested system while at the same time providing a realistic response of the heat distribution system.