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- Dahlblom, Mats, et al.
(författare)
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Distribution and variation of indoor temperatures in apartment blocks with individual metering and billing of space heating costs—on building, apartment, and room level
- 2015
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Ingår i: Energy Efficiency. - : Springer Science and Business Media LLC. - 1570-646X .- 1570-6478. ; 8:5, s. 859-880
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Tidskriftsartikel (refereegranskat)abstract
- A good indoor thermal climate is important. To reduce energy demands for space heating, individual metering and billing (IMB) for space heating costs is common, though not yet in Sweden. To obtain a better picture of the thermal climate conditions, the distribution of the measured indoor temperatures was investigated in each apartment in 14 apartment blocks with a total of 419 apartments. All blocks had an IMB system for space heating with a traditional feed-forward control. In the studied buildings, temperatures were measured in each living room and each bedroom, and were registered at 2.1 m over floor level, every 15 min over a period of 12 months. Seasonal mean temperatures, standard deviations, skewness, and kurtosis are presented for apartment blocks. For one, with 75 apartments, these values are monthly, and for January and April, the temperature range for each apartment is presented in boxplots. It can be concluded that there are variations in temperature between different apartments: both variations in temperature levels and in temperature ranges. The overall conclusions are that differences in indoor temperature are achievable for different apartments in an apartment block with a certain set point temperature and that the temperatures are not dependent on an apartment’s location in the building. Both the building owner’s goal to keep a certain average temperature for energy saving reasons, and the tenants’ goals, possibility to vary the indoor temperature at individual apartment level, seems to be possible to reach. The measured temperatures are close to being normally distributed, though they have a mild negative skewness and a mild kurtosis during heating periods. The results support that indoor temperatures can be modeled as normally distributed in energy simulations of buildings. Further, it can be seen that temperature variations follow the seasons. The temperatures on individual apartment level show that there is a tendency for warm apartments to be warm all the year round and vice versa. There are also daily variations, with a magnitude of 0.3–0.4 °C and with 0.1–0.3 °C difference between weekdays and weekends. Every single indoor temperature measurement for a whole year covering all seasons as a function of outdoor temperature is presented in iso-plots. Temperature levels are mainly within the limits of standards for thermal comfort, thus showing that a thermal satisfying indoor climate is met in these apartment blocks with IMB. It also seems that it was possible to achieve the desired temperatures irrespective of the apartment’s location.
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- Dahlblom, Mats, et al.
(författare)
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Evaluation of a feedback control method for hydronic heating systems based on indoor temperature measurements
- 2018
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788. ; 166, s. 23-34
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Tidskriftsartikel (refereegranskat)abstract
- Indoor temperatures in apartment blocks are often indirectly controlled by the outdoor temperature using a feedforward control loop, in which the radiator supply temperature is a function of the outdoor temperature. However, this control principle cannot take into account heat gains or losses caused by tenants, electrical appliances, the sun, air leakage, etc., which may result in uneven indoor temperatures, overheating, airing and increased energy use. This can be partly addressed by using thermostatic valves on each radiator. A municipal housing company in Sweden that uses individual metering and billing (IBM) of space heating costs based on measurements of indoor temperatures in all rooms of each apartment has been studied. This article presents and evaluates a project in which these measurements were used for feedback control. The aim of the study was to evaluate the principle which is based on using the actual indoor temperatures. An existing feedforward control of the heating system with thermostatic valves was enhanced by a correction of the supply temperature. The magnitude of the correction was proportional to the difference between the actual mean indoor temperature of the apartments and the set-point temperature. The enhanced control resulted in more constant indoor temperatures, i.e. they were less dependent on the outdoor temperature. The results support the conclusion that the evaluated method would be promising to apply in multi-family buildings. The introduction of the enhanced control method provided valuable experience and awareness of influencing factors if it were to be implemented on a larger scale.
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- Dahlblom, Mats, et al.
(författare)
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Variations in indoor temperature in residential apartments of different size and building category
- 2014
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Ingår i: NSB 2014 : 10th Nordic Symposium on Building Physics,15-19 June 2014 Lund, Sweden. - 9789188722539 ; , s. 830-837
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Konferensbidrag (refereegranskat)abstract
- In a case study, comprising 1177 residential apartments with 3248 rooms, temperature registrations every 15th minute in all living-rooms and bedrooms, during one year, in the system for individual metering and billing of space heating costs, were analyzed. The apartments were divided into two categories, apartment blocks from 1960th and row houses from about 1990. Apartments mean temperatures and standard deviations as a function of apartment size and category was compared. Corresponding was done on room level divided on apartment size for the two building categories. Finally, temperatures in bedrooms were compared to those in living-rooms for two objects from each category; presented in duration charts based on all single 15th minute values. The same pattern between different apartment sizes is kept for all month, though with a seasonal variation. The livingrooms are in mean warmer than bedrooms. The larger the apartments are the larger are the differences. The results provide a more nuanced picture of the temperature conditions in homes beneficial for better input data for building energy simulations.
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- Dahlblom, Mats, et al.
(författare)
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Vertical temperature gradients in apartments with hydronic radiator heating
- 2019
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Ingår i: Cold Climate HVAC 2018 : Sustainable Buildings in Cold Climates - Sustainable Buildings in Cold Climates. - Cham : Springer International Publishing. - 9783030006617 - 9783030006624 ; , s. 575-585
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Konferensbidrag (refereegranskat)abstract
- A vertical temperature stratification normally exists in rooms during the heat-ing season in cold climates. An expression of the gradient in apartments heated by hydronic radiator heating systems with exhaust ventilation has ear-lier been developed assuming a dependency of the outdoor temperature. The expression was used by a public real estate owner when re-calculating meas-ured indoor temperature at 2.1 m above floor to 1.2 m above floor represent-ing the occupancy zone and used for individual metering and billing of space heating cost. To validate the suggested expression temperature measurements have been made at four heights in living rooms in apartments built in the 70’s. The heights includes 0.0, 0.1, 1.1 and 1.7 m above floor. The theoreti-cal expression has been compared to the full-scale measurements and in general the expression overestimates the vertical temperature gradient. The measured gradients are generally very low. The thermal comfort in the aspect of vertical temperature gradient is good for the studied period.
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- Ejlertsson, Ann-Marie, et al.
(författare)
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PERFORMANCE OF VENTILATION SYSTEMS IN A DAY-CARE CENTRE
- 2013
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Ingår i: [Host publication title missing].
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Konferensbidrag (refereegranskat)abstract
- The performance of four ventilation systems placed in the same building and equipped with plate heat exchangers were examined during spring of 2012. In addition to temperature measurements supply and exhaust air flows measurements were performed. The result shows, that the measured supply and exhaust air flows differ from the design values. Furthermore, the efficiencies of the ventilation units differ from the estimated. Although, the units are placed in the same building and subject to similar conditions, their performance is not comparable when the amount of measurements, when the damper is open or closed and when the reheater is turned on or off amongst the different ventilation units, is taken into account.
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- Fransson, Victor, et al.
(författare)
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Window-opening and indoor climate in new multifamily-dwellings : A questionnaire survey
- 2014
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Ingår i: NSB 2014 : 10th Nordic Symposium on Building Physics,15-19 June 2014 Lund, Sweden : Full Papers - 10th Nordic Symposium on Building Physics,15-19 June 2014 Lund, Sweden : Full Papers. - 0349-4950. - 9789188722539 ; :3061, s. 908-915
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Konferensbidrag (refereegranskat)abstract
- The apartment-block of Flagghusen in Malmö in the south of Sweden was built and designed with the intention to achieve a lower energy use compare to the regulations and a good indoor environment. The outcome of this ambition was evaluated in a first report in 2010 that showed that the overall notion of the perceived indoor climate in the apartments were good but that the measured energy use exceeded the estimated values. It was revealed that the residents air their apartments frequently and for extended periods of time, which was in congruence with the previously made nationwide questionnaire survey BETSI. This observation in combination with the exceeded energy use resulted in the wish for a more comprehensive questionnaire study with in-depth questions concerning the window-opening behavior. A second questionnaire study took place in the heating season of 2012. This study aims at showing the magnitude and frequency of the window opening and to delve in the reasons why residents air their apartments with this second study as basis.
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