The procedure for this research consist of three steps: preparation, comparison measurement and simulation results, and sensitivity analysis. In the preparation part was determined how to assess the several building and user parameters.
In the second phase was first investigated how large several heat flows could be to have an indication and expectation of them before the simulations were performed. Subsequently, the simulation model was build, run and the results compared with the measurement results.
The results are compared on energy use for space heating and indoor air temperature on the ground floor and first floor. The influence of deviations in several building and user parameters on the energy use for space heating is investigated in the sensitivity analyses part.
2.1 Part 1: Preparation
In this part are the chosen building and user parameters presented. Those are investigated for the sensitivity analyses, see Table 1. The reference for the upper value of the building parameters is also shown. The lower values for the building parameters were chosen by choosing lower performance values then the values obtained from the drawings and manufacturer data. The values were estimated by the information gathered from literature. No data could be found about the used window frame, so an estimation of the lower and upper value is made with the help of the passive house requirements. Of the glazing was known that the U-value was 0.6, but the G-value could be 0.65 or 0.5. So these values are used as lower and upper value. For the user behavior parameters were some cases made, to have an indication of the influence of the several user behavior parameters.
Table 1 – Investigated building and user parameters for the sensitivity analyses
Building parameters Lower value Upper value Reference upper
value
U-window frame [W/m2K] 1.1 0.8 Uw-value (Uf+Ug)
<0.8 passive house institute requirment Rc-value ground floor
[m2K/W]
2.5 3.5 Drawings Franke
Architecten Rc-value external wall
[m2K/W] 4.3 8.5 Drawings Franke Architecten Rc-value roof [m 2 K/W] 7.8 8.8 Drawings Franke Architecten
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Efficiency heat recovery [%] 75 94 Manufacturer Storkair of WHR 930 Infiltration rate [n50- value] 2.0 1.0 Measured by Franke Architecten
G-value glazing 0.65 0.5 Manufacturer
Noorddennegroep User parameters
Window use bedroom occupants
Window always closed Window always opened ajar
Thermostat set point in the whole house
19°C with measured thermostat use profile
23°C with measured thermostat use profile Set point ventilation
system
Always set point 1 Always set point 3
Heat gain electricity use as measured 2 times the measured
value
2.2 Part 2: Comparison measurement and simulation results
Before the comparison of the measurement and simulation results was investigated what results could be expected. This was done by hand calculations. Therefore several heat flows were calculated. For these calculations the same values were used as in the simulation model of dwelling H0300. The calculated heat flows are:
-Heat gains from electricity, people and heating system.
-Heat losses through external walls, ground floor, glazing and frame, mechanical ventilation with heat recovery and mechanical ventilation without heat recovery due to an unbalanced ventilation system.
- Heat flow through partition walls. The thermal conductance of the partition walls in the three zones was calculated. The heat loss could not be calculated, because the temperatures in the houses of the neighbors were not known.
To have an indication how large the heat losses/gains are through partition walls, infiltration, and ventilation via window and doors, a heat balance was made for the month January:
Gains: Electricity + People + Solar radiation + Heating system + (Partition walls) =
Losses: (Partition walls) + Ground floor slab + Glazing and frame + MVHR + MV without HR + Infiltration + Ventilation via windows/doors
To fill in this heat balance the gain of solar radiation also had to be known. Therefore the calculated solar radiation by the simulation model was used.
When the hand calculation part was done, the simulations were performed. The simulated dwellings for this study were H0300,H0500 and H0700. This were all dwellings of type 506. In this main paper especially dwelling H0300 was discussed, because the three dwellings were on most points the same. The model input of H0300 can be found in Appendix A. Deviation in the models of H500 and H0700 with respect to H0300 are included in Appendix B. In each of the three simulated dwellings lives an older men and women, who are retired. Information about the building shell and dimensions of the dwelling were gathered from drawings and manufacturer information. The outside air temperature, relative humidity, solar radiation and wind speed were measured every 10 minutes on an apartment building in the district Kroeven in Roosendaal.
In Figure 1 is shown what was measured in dwelling H0300 every 3 minutes. Only the total gas and electricity use was measured every hour.
Further in dwelling H0300 was measured:
-The ventilation flows of the mechanical ventilation system in all three set points measured on 24-10- 2012 with a flow finder.
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Figure 1 – measurement set up of dwelling H0300.
Based on the measurements could be determined:
- Use of the set points of the ventilation system by the occupants could be determined from the measured electricity use of the ventilation system.
- Average user profile for electricity and window use was determined and used in the simulation model, see Appendix A. It’s assumed that all the used electricity was converted in heat as heat gain. - Thermostat set point at daytime and nighttime was determined from the measured air temperature in the living room, see Appendix A.
- Whether people were on the ground floor or on the first floor was determined out of the
thermostat use and window use in their bedroom. It was assumed in the simulation model that they were never on the attic.
Also a structured interview was done, to be able to control the measurements and to decrease the uncertainty in actual user behavior. For example, a never opened window (in accordance to the measurements) could be checked by asking the question which windows they used for extra ventilation. The interview can be found in Appendix E of the former study.
After gathering data about H0300, the dwelling was modeled in the tool IES-VE 6.4. The model deviates at points of the reality, because of simplifications or a lack on better data. A simplification is for example that the building was split up in three zones: ground floor, first floor and attic instead of nine zones in reality.
Finally, the measurement results were compared with the results of the simulation models. This comparison shows how large the deviation of the model is, with reality on energy use for space heating and indoor air temperatures. The simulated air temperatures and surface temperatures are given, because the measurement equipment of the air temperature was mounted on the wall and by this was the measured air temperature possible influenced by the wall.
The comparison of the measurement results and simulation results of dwelling H0500 and H0700 can be found in Appendix B.
2.3 Part 3: Sensitivity analysis
In this last step were the sensitivity analyses performed for the parameters presented in Table 1 in paragraph 2.1. The sensitivity analyses were carried out with the simulation model of H0300, for the period January-May. For each parameter was first the lower value simulated and afterwards the upper value. The difference in energy use between those two was used to have an indication of the sensitivity of that parameter.
3. RESULTS
The results of the comparison of the measurement and simulation results of step 1 and the results of the sensitivity analyses of step 2 are presented below. The results presented below are only results of dwelling H0300.
5 3.1 Comparison measurement and simulation results
In this paragraph the results of the hand calculations are shown first, see Table 2-5. In Table 2 the results are shown of the several calculated heat gains and losses for the months January-May. In Table 3 the thermal conductance is shown of both partition walls per zone. An example of the heat loss through these walls in the period January-May is presented in Table 4, because the air
temperatures in the dwellings of the neighbors is not known and therefore the real heat gain/heat loss cannot be calculated. The heat balance of the heat gains and heat losses of dwelling H0300 in the month January is shown in Table 5. The whole hand calculations can be found in Appendix C. The measurement and simulation results are shown in Table 6 and Figure 2-5. Table 6 shows the measured and simulated energy use for space heating per month. Figure 2 shows the measured and simulated air temperature of the ground floor during the month January and in Figure 3 is zoomed in on 14-1-2013. Figure 4 shows the measured and simulated air temperature of the first floor during the month January and in Figure 5 is zoomed in on 14-1-2013. The remaining measurement and simulation results of the indoor temperatures for the months February-May of H0300 are presented in Appendix D.
Table 2 – Results of the hand calculations of the several heat gains and heat losses per month of dwelling H0300.
Electricity use [kWh] People [kWh] Heating system [kWh] External walls [kWh] Ground floor [kWh] Glazing and frame [kWh] Mechanical ventilation with heat recovery [kWh] Mechanical ventilation without heat recovery [kWh] January 276 147 1048 159 76 228 31 248 February 248 133 927 146 69 208 27 225 March 281 147 848 153 77 219 28 237 April 268 142 370 100 73 144 19 155 May 267 147 122 80 76 114 15 123
Table 3 – Thermal conductance of both partition walls of dwelling H0300, Upartition wall is 6.50 W/m 2
K
Surface area partition wall both sides [m2] [W/K] Ground floor 36.7 239 First floor 33.6 218 Attic 19.5 127 Total 89.8 584
Table 4 - Example of heat loss when in both neighbors’ houses of dwelling H0300, the temperature is one Kelvin lower during January-May.
Heat loss when in both neighbors’ houses the temperature is continuously 1 Kelvin lower [kWh]
January 434
February 392
March 434
April 420
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Table 5 – Heat balance of the heat gains and heat losses of dwelling H0300 in the month January. The heat losses and heat gains with the symbol ? are not calculated.
Heat loss [kWh] Heat gain [kWh]
Electricity use 276
People 147
Solar radiation 81
Heating system 1048
Partition walls ? ?
Ground floor slab 76
Glazing and frame 228
Mechanical ventilation with heat recovery
31
Mechanical ventilation without heat recovery
248
Infiltration ?
Ventilation via windows/doors ?
Total 583 1552
Table 6 - The energy use for space heating per month, determined from measured data and simulations
Measured energy use for space heating [kWh]
Simulated energy use for space heating [kWh]
January 1048 950 February 927 820 March 848 774 April 370 359 May 122 246 Total 3315 3149
Figure 2 - The measured air temperatures in the living room, and the simulated air temperatures and surface temperature in the ground floor zone for the month January.
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Figure 3 - The measured air temperatures in the living room, and the simulated air temperatures and surface temperature in the ground floor zone on 14-01-2013.
Figure 4 - The average measured air temperatures in two bedrooms at the first floor, and the simulated air temperatures and surface temperatures in the first floor zone, for the month January.
Figure 5 - The average measured air temperatures in two bedrooms at the first floor, and the simulated air temperatures and surface temperatures in the first floor zone on 14-01-2013.
8 3.2 Sensitivity analysis
In this paragraph the results are presented of the sensitivity analysis. The difference in energy use for space heating for the upper and lower boundary is given per parameter in Figure 6.
Figure 6 – Sensitivity analyses results of several building and user parameters showing the difference in energy use for space heating between the upper and lower value.