• Energy Research
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Abstract The use of pre-set thermostatic radiator valves (TRVs) contributes to the reduction of energy consumption and the increase of the energy efficiency of the existing heating systems in buildings. However, there are limited long-term experimental studies that document the level of energy savings achieved by the use of TRVs, quantified for three different options of their utilisation. Long-term field data were collected over several heating seasons from nine existing multifamily residential buildings organized into three groups characterized by different modernization activities using TRVs. The first group includes the cases where the buildings are equipped with TRVs without hydraulic balance of the heating system with pre-set TRVs; the second group encompasses buildings that were already equipped with TRVs and then a hydraulic balancing of the heating system was performed by means of a pre-set; finally, the third group of buildings considers the simultaneous installation of TRVs and hydraulic balancing of the heating system using pre-set TRVs. The energy savings ranged between 7.1% and 23.3%, depending on the range of modernization activities using TRVs with or without hydraulic balance. The payback time was less than 2.5 heating seasons in all cases.

Abstract The use of pre-set thermostatic radiator valves (TRVs) contributes to the reduction of energy consumption and the increase of the energy efficiency of the existing heating systems in buildings. However, there are limited long-term experimental studies that document the level of energy savings achieved by the use of TRVs, quantified for three different options of their utilisation. Long-term field data were collected over several heating seasons from nine existing multifamily residential buildings organized into three groups characterized by different modernization activities using TRVs. The first group includes the cases where the buildings are equipped with TRVs without hydraulic balance of the heating system with pre-set TRVs; the second group encompasses buildings that were already equipped with TRVs and then a hydraulic balancing of the heating system was performed by means of a pre-set; finally, the third group of buildings considers the simultaneous installation of TRVs and hydraulic balancing of the heating system using pre-set TRVs. The energy savings ranged between 7.1% and 23.3%, depending on the range of modernization activities using TRVs with or without hydraulic balance. The payback time was less than 2.5 heating seasons in all cases.

Increasing the level of energy efficiency and using renewable energy sources in the design and existing buildings is an important aspect in minimizing the carbon dioxide emissions and mitigating the climate changes. One of such solutions may be the application of a heating system using residential thermal stations (RTSs) for heating and hot water preparation individually in the premises of a given building. The main purpose of this paper was to analyze long-term filed research results on the energy consumption and efficiency of heating systems in a dormitory (building B1) and two multifamily buildings (building B2 and B3) equipped with residential thermal stations (RTSs) that are used for supplying individual dwellings with heat, as well as hot and cold water. An additional aspect of the analysis is a presentation of the structure of total energy consumption for particular purposes in the analyzed buildings and the possibilities to increase the share of renewable energy sources using solar thermal collectors for supporting the analyzed heating system.

Increasing the level of energy efficiency and using renewable energy sources in the design and existing buildings is an important aspect in minimizing the carbon dioxide emissions and mitigating the climate changes. One of such solutions may be the application of a heating system using residential thermal stations (RTSs) for heating and hot water preparation individually in the premises of a given building. The main purpose of this paper was to analyze long-term filed research results on the energy consumption and efficiency of heating systems in a dormitory (building B1) and two multifamily buildings (building B2 and B3) equipped with residential thermal stations (RTSs) that are used for supplying individual dwellings with heat, as well as hot and cold water. An additional aspect of the analysis is a presentation of the structure of total energy consumption for particular purposes in the analyzed buildings and the possibilities to increase the share of renewable energy sources using solar thermal collectors for supporting the analyzed heating system.

Nowadays, the attention of designers and service providers is especially focused on energy efficiency and integration of renewable energy sources (RES). However, the knowledge on smart devices and automated, easily applicable algorithms for optimizing heating consumption by effectively taking advantage of solar heat gains, while avoiding overheating, is limited. This paper presents a simple method for taking into account the influence of solar heat gains in the form of solar radiation for the purposes of forecasting or controlling thermal power for heating of buildings. On the basis of field research carried out for seven buildings (five residential buildings and two public buildings) during one heating season, it was noticed that it was justified to properly narrow down the input data range included in the building energy model calculations in order to obtain a higher accuracy of calculations. In order to minimize the impact of other external factors (in particular wind speed) affecting the heat consumption for heating purposes, it was recommended to consider the data range only at wind speeds below 3 m/s. On the other hand, in order to minimize the impact of internal factors (in particular the impact of users), it was suggested to further narrow down the scope of the input data to an hour (e.g., 10–14 in multi-family residential buildings). During these hours, the impact on users was minimized as most of them were outside the building.

Nowadays, the attention of designers and service providers is especially focused on energy efficiency and integration of renewable energy sources (RES). However, the knowledge on smart devices and automated, easily applicable algorithms for optimizing heating consumption by effectively taking advantage of solar heat gains, while avoiding overheating, is limited. This paper presents a simple method for taking into account the influence of solar heat gains in the form of solar radiation for the purposes of forecasting or controlling thermal power for heating of buildings. On the basis of field research carried out for seven buildings (five residential buildings and two public buildings) during one heating season, it was noticed that it was justified to properly narrow down the input data range included in the building energy model calculations in order to obtain a higher accuracy of calculations. In order to minimize the impact of other external factors (in particular wind speed) affecting the heat consumption for heating purposes, it was recommended to consider the data range only at wind speeds below 3 m/s. On the other hand, in order to minimize the impact of internal factors (in particular the impact of users), it was suggested to further narrow down the scope of the input data to an hour (e.g., 10–14 in multi-family residential buildings). During these hours, the impact on users was minimized as most of them were outside the building.

The radiant floor heating/cooling systems are more often used in new designed and modernized buildings, what renewed the interest in the study of the characteristic parameters, which are taking in to account by dimensioning or detailed scientific analyzes of such a systems. Very important and fundamental characteristic parameters for radiant floor are heat transfer coefficients. This article presents the results of experimental research on heated/cooled radiant floor conducted in the laboratory room in the climatic chamber, which aim was to estimate experimentally the values of heat transfer coefficients for the surface of cooled/heated radiant floor. The values of radiant, convective and total heat transfer coefficients were developed on the basis of the amount of heat emitted from the radiant surface and by the use of proper and clearly defined reference temperature depending on the kind of heat transfer coefficient. It was noticed, that the values of heat transfer coefficients for heated/cooled radiant floor, which are commonly used in practice, are overestimated, even in the range of 10–30%.

The radiant floor heating/cooling systems are more often used in new designed and modernized buildings, what renewed the interest in the study of the characteristic parameters, which are taking in to account by dimensioning or detailed scientific analyzes of such a systems. Very important and fundamental characteristic parameters for radiant floor are heat transfer coefficients. This article presents the results of experimental research on heated/cooled radiant floor conducted in the laboratory room in the climatic chamber, which aim was to estimate experimentally the values of heat transfer coefficients for the surface of cooled/heated radiant floor. The values of radiant, convective and total heat transfer coefficients were developed on the basis of the amount of heat emitted from the radiant surface and by the use of proper and clearly defined reference temperature depending on the kind of heat transfer coefficient. It was noticed, that the values of heat transfer coefficients for heated/cooled radiant floor, which are commonly used in practice, are overestimated, even in the range of 10–30%.