Puerto Príncipe, Haití
“EL MISTERIO DEL CUMPLIMIENTO DE LA SEGUNDA VENIDA DE CRISTO.” Ese es nuestro tema
Fig.4.22 shows the total energy consumption of the building for a whole year (November 2016 - October 2017) in terms of electricity and gas usage. There were some missing data from the monitoring study on electric consumption between January 2017 and April 2017. For that period, information was provided by the occupants based on meter readings. Moreover, the house was unoccupied during March and April 2017. The results of the electricity consumption (Fig.4.22a) showed that, during cold weather, the monthly electricity usage was between 250kWh and 300kWh and during warm weather between 125kWh and 150kWh. Based on the electricity provider’s charges, this translates to a cost of £45 - £55 (including standard charges) during winter and an average of £25 per month during warm and moderate months. The total
annual electricity consumption of the house was calculated to be 2015kWh (£391). The average annual electricity consumption in a typical UK household is calculated to around 3,828 kWh (BEIS, 2018).
With regard to the gas usage (Fig.4.22b), the monthly consumption was between 1000kWh and 1500kWh during winter, with a maximum of 2000kWh in January, the coldest month. During warm and moderate weather there was no heating demand and gas was only used for DHW; the average consumption was around 450kWh. The gas consumption translates to a cost of £50 - £80 during winter and an average monthly cost of £20 for the rest of the year. The total annual gas consumption of the building was 8425kWh (£430). The average annual gas consumption in the UK domestic sector is calculated to around 12,609 kWh (BEIS, 2018).
Figure 4.22 Monthly breakdown of building’s energy consumption for a year (November 2016 to October 2017). The primary vertical axis on the left illustrates the usage in kWh and the secondary vertical axis on
Fig.4.23 shows the daily gas consumption for the building for space heating and DHW. During winter, the daily gas consumption varied between 30kWh and 60kWh, with an average of 35kWh. During moderate and warm weather there was no heating demand and all gas usage was attributed to DHW, which was calculated to an average of 20kWh per day throughout the whole year. Fig. 4.24 shows the daily electricity consumption of the MVHR system. During winter, the electricity consumed by the MVHR unit varied between 0.1kWh and 0.9kWh per day (with an average of 0.45kWh). During moderate and warm weather, the electricity consumption of the MVHR system was somewhat more stable, at around 0.45kWh per day. The daily energy consumption of the building for space heating (including the electricity consumption of the MVHR unit) was an average of 35.45kWh per day during the cold period. This translates to a specific heating demand of 0.13kWh/m2.day. Assuming the heating period lasts between November and February, the annual specific heating demand of the building is around 15.6kWh/m2.yr, which is indeed very close to Passivhaus standard (i.e. Specific Heating Demand ≤ 15kWh/m2.yr (Passivhaus, n.d.).
Figure 4.23 Daily breakdown of gas consumption for a year (November 2016 to October 2017). Energy used for heating and DHW.
Figure 4.24 Daily breakdown of MVHR electricity consumption for a year (November 2016 to October 2017).
4.3.6
SUMMARY
The monitoring study showed that the ICF building fabric of Twiga Lodge was able to moderate significantly the internal air temperature swings, providing a stable internal environment. The average internal air temperature was calculated between 22oC and 25oC during summer and around 21oC during winter. The diurnal external temperature was found to fluctuate significantly during the whole year; however, the daily internal air temperature variations were significantly reduced during the whole of the year.
During summer, there were small differences in the daily internal air temperature of the three spaces included in the analysis. In winter, however, the shading devices were found to affect significantly the performance of the rooms. The zones without shading showed increased diurnal internal air temperature fluctuations during days with increased solar availability. Furthermore, the internal gains in the space had a significant impact on the daily diurnal temperature variation of the internal air temperature. More specifically, in the kitchen, where the internal gains are high, the daily fluctuation of the zone air temperature was higher during both summer and winter, compared to the other rooms.
internal air temperature by an average of 1 hour from the time of the maximum external air temperature during the whole year. Usually, high thermal mass structures delay the time that the peak internal temperature occurs by several hours compared to the time of the peak external temperature. One-hour delay indicates a relatively quick response of the fabric, usually representative of low thermal storage capacity. However, when looking at the spread between the different daily values of the time span, it becomes apparent that the decrement delay of the ICF fabric is very much influenced by changes in boundary conditions. Hence, no solid conclusions can be drawn on the slow (or quick) response of the fabric to changes in surrounding environment.
The findings of this WP addressed Objective No2 and showed that the ICF fabric dampened significantly the high external temperature swings, providing a stable internal environment. However, it should be acknowledged that there are several factors that could affect the thermal performance of a building, such as the magnitude of internal heat gains, the levels of ventilation, the design of the building and so on. For the specific case study and for the specific building operation, the results of this work package indicated a relatively steady internal air environment pointing towards the positive impact of the ICF fabric in moderating internal temperature swings. Moreover, the analysis of the building’s energy consumption confirmed that Twiga Lodge is indeed a low-energy building operating near to Passivhaus standards.