scholarly journals Real Domestic Hot Water Consumption in Residential Buildings and Its Impact on Buildings’ Energy Performance—Case Study in Poland

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5010
Author(s):  
Katarzyna Ratajczak ◽  
Katarzyna Michalak ◽  
Michał Narojczyk ◽  
Łukasz Amanowicz
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Water Consumption ◽  
Residential Buildings ◽  
Energy Performance ◽  
Primary Energy ◽  
Hot Water ◽  
Domestic Hot Water ◽  
Total Energy Balance ◽  
Consumption Rates

A building’s energy consumption is assessed considering the energy required for heating, cooling, lighting, and domestic hot water (DHW). Methodologies used to calculate energy certificates in European Union countries consider hot water consumption rates per person or per heated (floor) area, giving wide-ranging values (35–88 dm3/person/day). Using extreme parameters, it is possible to obtain a primary energy index that meets the legal requirements, although unrealistically large proportions of domestic hot water use relative to the total energy balance of the building may marginalize the influence of other components, such as fluctuations in heating, ventilation, or lighting. In the current work, the DHW consumption of three residential buildings was measured to verify the energy consumption for hot water preparation. Investigations were conducted based on the consumption of natural gas for DHW preparation. Experimentally obtained water consumption rates were determined per m2 of a dwelling and per person living in the building. The calculated indicators (0.85 ± 0.005 dm3/m2/day and 27.4 ± 1.4 dm3/person/day) were lower than those used for energy certifications of buildings. The experimentally obtained indicators were used in further theoretical energy assessments of six residential buildings. By adopting the designated indicators, the analyzed buildings met the legally required primary energy value (<70 kWh/m2/year) when using natural gas as a heat source. Applying more realistic DHW consumption values resulted in more accurate energy certifications.

scholarly journals Energy Performance Optimization in a Condensing Boiler

2021 ◽  
Vol 9 (1) ◽  
pp. 6
Author(s):  
Diego Fernández-Cheliz ◽  
Eloy Velasco-Gómez ◽  
Juan Peral-Andrés ◽  
Ana Tejero-González
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Performance Optimization ◽  
Energy Performance ◽  
Primary Energy ◽  
Operating Conditions ◽  
Hot Water ◽  
Operating Parameters ◽  
Climate Conditions ◽  
Lower Heating Value

In Europe, primary energy consumption in buildings accounts for up to 25–40%, depending on the climate conditions. Space heating and Domestic Hot Water (DHW) contribute significantly to this energy consumption. Among the most common sources for heat generation in these appliances is natural gas. Condensing boilers can surpass the 100% energy performance over the lower heating value, if the operating conditions enable the water vapor in the exhaust gases to condensate. Consequently, optimizing the operating parameters of condensing boilers is necessary to decrease fuel consumption without hindering water heating needs. The present work presents an experimental approach to the operating parameters of a condensing boiler that works with natural gas. The aim is to develop a theoretical model that relates the energy performance to the water temperature set by the final user and the excess air set by the maintenance staff.

scholarly journals Determination of the Energy Performance of a Solar Low Energy House with Regard to Aspects of Energy Efficiency and Smartness of the House

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3232
Author(s):  
Dorota Chwieduk ◽  
Michał Chwieduk
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Solar Energy ◽  
Residential Buildings ◽  
Energy Performance ◽  
Primary Energy ◽  
Hot Water ◽  
Low Energy ◽  
Primary Energy Consumption

The paper shows how difficult it is to prove technically that a building really is both low energy and smart, and that all aspects of energy efficiency have been treated equally. Regulations connected to the determination of the energy performance of residential buildings take into account only space and hot water heating energy consumption and define the indices of maximal primary energy consumption, but not energy needs based on the architecture of the building. A single family house designed and constructed as a low energy solar house in Warsaw’s suburbs is considered. Availability of solar energy and its influence on the architecture of the house is analyzed. A specific solar passive architectural concept with solar southern and cold northern buffer spaces incorporated into the interior of the house is presented. Parameters of the building’s structure, construction materials, as well as operation parameters of equipment and heating systems based on active use of solar energy, ground energy (via a heat pump) and waste heat from a ventilation system are described. Results of calculations give values of final and primary energy consumption index levels of 11.58 kWh/m2 and 25.77 kWh/m2, respectively. However, the official methodology for determination of energy performance does not allow for presenting how energy efficient and smart the building really is.

scholarly journals A Statistical Approach for Selecting Buildings for Experimental Measurement of HVAC Needs

2017 ◽  
Vol 24 (1) ◽  
pp. 99-116
Author(s):  
Paweł Malinowski ◽  
Piotr Ziembicki
Keyword(s):  
Energy Consumption ◽  
Experimental Measurement ◽  
Numerical Experiments ◽  
Statistical Approach ◽  
Residential Buildings ◽  
Hvac Systems ◽  
Hot Water ◽  
Statistical Methodology ◽  
Domestic Hot Water ◽  
Water Demands

Abstract This article presents a statistical methodology for selecting representative buildings for experimentally evaluating the performance of HVAC systems, especially in terms of energy consumption. The proposed approach is based on the k-means method. The algorithm for this method is conceptually simple, allowing it to be easily implemented. The method can be applied to large quantities of data with unknown distributions. The method was tested using numerical experiments to determine the hourly, daily, and yearly heat values and the domestic hot water demands of residential buildings in Poland. Due to its simplicity, the proposed approach is very promising for use in engineering applications and is applicable to testing the performance of many HVAC systems.

scholarly journals Heat Pump Water Heater For Cold Climate – Canada

2021 ◽  
Author(s):  
Afarin Amirirad
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Residential Buildings ◽  
Minimum Energy ◽  
Cold Climate ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Heater ◽  
Domestic Hot Water ◽  
Heat Pump Water Heater

Considering the large energy consumption of conventional water heaters in residential buildings, the performance of a new type of water heater has been characterized through conducting experiments and numerical modelling. The specific water heater investigated in this work benefits from heat absorption from the indoor air, denoted as the air source heat pump water heater (ASHPWH), and is located in the Archetype Sustainable Twin House B in Toronto. The experiments have been conducted under three different indoor conditions associated with temperature and humidity. The coefficient of performance (COP), which quantifies the ratio of heating capacity to the consumed power of ASHPWH, ranges between 1.5 and 5, depending on the indoor dry bulb and water inlet temperatures. A TRNSYS model of ASHPWH has been constructed based on the obtained experimental results and has subsequently been integrated with a TRNSYS model of the Archetype Sustainable House (ASH). The numerical results were verified with the experimental data. The model results suggests that after employing ASHPWH, the domestic hot water energy consumption reduces by 60.3% and 53.2% compared to the electric water heater in summer and winter respectively. Due to the energy absorption of ASHPWH from the indoor environment, the heating load of the ASH house increases while its cooling load decreases. Furthermore, the annual electricity consumption of the ASH house due to the required heating and cooling as well as the domestic hot water demand is reduced by 21.3%. Finally, as a consequence of employing ASHPWH, the energy cost and GHG emission were reduced respectively by 22% and 21.7%. By investigating the system in four other Canadian cities, it appears that Vancouver and Edmonton would have the maximum and minimum energy savings respectively.

scholarly journals Heat Pump Water Heater For Cold Climate – Canada

2021 ◽  
Author(s):  
Afarin Amirirad
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Residential Buildings ◽  
Minimum Energy ◽  
Cold Climate ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Heater ◽  
Domestic Hot Water ◽  
Heat Pump Water Heater

Considering the large energy consumption of conventional water heaters in residential buildings, the performance of a new type of water heater has been characterized through conducting experiments and numerical modelling. The specific water heater investigated in this work benefits from heat absorption from the indoor air, denoted as the air source heat pump water heater (ASHPWH), and is located in the Archetype Sustainable Twin House B in Toronto. The experiments have been conducted under three different indoor conditions associated with temperature and humidity. The coefficient of performance (COP), which quantifies the ratio of heating capacity to the consumed power of ASHPWH, ranges between 1.5 and 5, depending on the indoor dry bulb and water inlet temperatures. A TRNSYS model of ASHPWH has been constructed based on the obtained experimental results and has subsequently been integrated with a TRNSYS model of the Archetype Sustainable House (ASH). The numerical results were verified with the experimental data. The model results suggests that after employing ASHPWH, the domestic hot water energy consumption reduces by 60.3% and 53.2% compared to the electric water heater in summer and winter respectively. Due to the energy absorption of ASHPWH from the indoor environment, the heating load of the ASH house increases while its cooling load decreases. Furthermore, the annual electricity consumption of the ASH house due to the required heating and cooling as well as the domestic hot water demand is reduced by 21.3%. Finally, as a consequence of employing ASHPWH, the energy cost and GHG emission were reduced respectively by 22% and 21.7%. By investigating the system in four other Canadian cities, it appears that Vancouver and Edmonton would have the maximum and minimum energy savings respectively.

scholarly journals Integration of Micro-Cogeneration Units and Electric Storages into a Micro-Scale Residential Solar District Heating System Operating with a Seasonal Thermal Storage

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5456
Author(s):  
Antonio Rosato ◽  
Antonio Ciervo ◽  
Giovanni Ciampi ◽  
Michelangelo Scorpio ◽  
Sergio Sibilio
Keyword(s):  
Natural Gas ◽  
Residential Buildings ◽  
Electric Energy ◽  
District Heating ◽  
Thermal Storage ◽  
Hot Water ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Micro Scale ◽  
Gas Fueled

A micro-scale district heating network based on the operation of solar thermal collectors coupled to a long-term borehole thermal storage is modeled, simulated and investigated over a period of five years. The plant is devoted to covering the domestic hot water and space heating demands of a district composed of six typical residential buildings located in Naples (southern Italy). Three alternative natural gas-fueled back-up auxiliary systems (condensing boiler and two different technologies of micro-cogeneration) aiming at balancing the solar energy intermittency are investigated. The utilization of electric storages in combination with the cogeneration systems is also considered with the aim of improving the self-consumption of cogenerated electric energy; heat recovery from the distribution circuit is also evaluated to pre-heat the mains water for domestic hot water production. The performances of the proposed plant schemes are contrasted with those of a typical Italian decentralized heating plant (based on the utilization of natural gas-fueled non-condensing boilers). The comparison highlighted that the proposed configurations can decrease the primary energy consumption (up to 11.3%), the equivalent emissions of carbon dioxide (up to 11.3%), and the operation costs (up to 14.3%), together with an acceptable simple pay-back period (about 4.4 years).

scholarly journals Analysis of the scope of thermo-modernization for a residential building in order to transform it into a low-energy building

2018 ◽  
Vol 44 ◽  
pp. 00069 ◽  
Author(s):  
Maciej Knapik
Keyword(s):  
Energy Demand ◽  
Residential Buildings ◽  
Residential Building ◽  
Building Design ◽  
Primary Energy ◽  
Hot Water ◽  
Low Energy ◽  
Existing Building ◽  
Domestic Hot Water ◽  
Modernization Process

The article presents the problem of thermo-modernization and the reduction of energy demand for heating purposes in existing residential buildings. The thermo-modernization process has to adapt the existing building to the standard of a building with low energy demand and applicable regulations. Low-energy constructions are a result of introduction of new solutions in building design process. Their main objective is to achieve a significant reduction in demand for renewable primary energy, necessary to cover the needs of these buildings, mostly related to their heating, ventilation and domestic hot water. The article presents the results of the analysis and calculation of selected thermo-modernization variants. The results showed that thermo-modernization process of existing residential buildings is justified both energetically and economically.

scholarly journals Experimental Study and Modeling of Ground-Source Heat Pumps with Combi-Storage in Buildings

2018 ◽  
Author(s):  
Wessam El-Baz ◽  
Peter Tzscheutschler ◽  
Ulrich Wagner
Keyword(s):  
Heat Pump ◽  
Water Consumption ◽  
Residential Buildings ◽  
Heat Pumps ◽  
Hot Water ◽  
Space Heating ◽  
Ground Source Heat Pumps ◽  
Domestic Hot Water ◽  
Ground Source ◽  
And Control

There is a continuous growth of heat pump installations in residential buildings in Germany. The heat pumps were not only used for space heating and domestic hot water consumption but also to offer flexibility to the grid. the high coefficient of performance and the low cost of heat storages made the heat pumps an optimal candidate for the power to heat applications. Thus, several questions are raised about the optimal integration and control of the heat pump system with buffer storages to maximize its operation efficiency and minimize the operation costs. In this paper, an experimental investigation is performed to study the performance of a ground source heat pump (GSHP) with a combi-storage under several configurations and control factors. The experiments were performed on an innovative modular testbed that is capable of emulating a ground source to provide the heat pump with different temperature levels at different times of the day. Moreover, it can emulate the different building loads such as the space heating load and the domestic hot water consumption in real-time. The data gathered from the testbed and different experimental studies were used to develop a simulation model based on Modelica that can accurately simulate the dynamics of a GSHP in a building. The model was validated based on different metrics. Energetically, the difference between the developed model and the measured values was only 3.08\% and 4.18\% for the heat generation and electricity consumption, respectively.

scholarly journals Predicting Domestic Hot Water Demand Using Machine Learning for Predictive Control Purposes

Proceedings ◽  
2019 ◽  
Vol 23 (1) ◽  
pp. 6 ◽  
Author(s):  
Louis-Gabriel Maltais ◽  
Louis Gosselin
Keyword(s):  
Neural Network ◽  
Energy Consumption ◽  
Predictive Control ◽  
Recurrent Neural Network ◽  
Water Consumption ◽  
Water Demand ◽  
Hot Water ◽  
Quebec City ◽  
Predicting Model ◽  
Domestic Hot Water

An important part of a building energy consumption is related to the domestic hot water consumption of its occupants. Predictive controllers are often considered as having the potential to reduce the energy consumption of hot water systems. In this work, a recurrent neural network is trained from the measured domestic hot water consumption of a 40 unit residential building in Quebec City, Canada, to predict the future consumption. It is found that the water consumption profile of the building changes from day to day throughout the year and has an important noise component. A predicting model is developed in this work and is obtained by pairing a recurrent neural network to predict the filtered domestic hot water demand with a random forest to predict the noise signal. The evaluated performances indices for the prediction of the next demand are satisfying (i.e., RMSE of 142.02 L/h and R2 of 0.71). In addition, it is found that the predictions made over the following hour using the same predicting model are accurate and could likely be used in a predictive control context.

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