Building Heating Systems Research Articles

Analysis of the Impact of High-Space Building Heating System Solutions on Building Energy Efficiency

The existence of stratification in high-ceiling buildings is real, but not visible or easy noticeable by humans. For field measurements, the Prayer House – The Kaunas Basilica of the Resurrection of Christ, located in Kaunas, Lithuania, was chosen, in which the temperature distribution at different heights (6 m, 8 m, 10 m, 12 m, 14 m, 16 m and 18 m) during the heating season was observed. The Basilica had radiant heaters installed at 5 m height. According to the plan of the Prayer House, CFD model was created, and the temperature distribution of the different heating (radiant heating and floor heating) systems were compared. The IDA-ICE modelling of energy consumption was conducted using the CFD results as a basis, and the economic analysis was performed based on the obtained results. The study confirmed the existence of stratification in high-ceiling buildings.

Verification of Energy Efficiency as a Function of the Control Mode of a Residential Heating System, Modelled in a MATLAB SIMULINK Environment

Efficient control of the heating system in residential buildings is of outstanding importance for energy efficiency, comfort, and emissions reduction. The use of mathematical modelling and simulation allows for the investigation and optimization of various heating control modes. During the study, we developed mathematical models to describe different control modes of the heating system in residential buildings. The most commonly used modes were constant setpoint control, variable setpoint control, weather-compensation control, and PID control. Among these, we compared the constant setpoint On/Off thermostat control with the variable setpoint control based on normal and reduced temperature time programs.Based on the models, we analysed the effectiveness and energy-saving potential of these two different control modes. The simulations were conducted using meteorological measurement data. The results showed that the variable setpoint control leads to 8,4% energy saving with minimal or negligible decrease in comfort, thus ensuring lower emissions.It can be concluded that through mathematical modelling and simulation, it is possible to conduct detailed examinations and comparisons of the heating system control modes in residential buildings. Based on the findings, designers and engineers can develop more efficient and sustainable heating solutions for residential buildings.

Active solar heating system for residential building in Algeria An energetic economic and environmental investigation

In this work we used a typical single family house in Algeria as an example, the influence of building type on the energetic efficiency of an integrated solar combisystem (SCS) is determined by means of numerical simulation using TRNSYS software program. We considered two types of buildings, which have the same size and the same orientation. The first one is a low energy pilot house performed by CDER 'Centre de Développement des Energies Renouvelables' and CNERIB 'Centre National d’Etudes et Recherches Intégrées du Bâtiment' in the framework of MED-ENEC project, however, the second considered house is a virtual building; in which the walls are of the conventional type in Algeria. Based on the obtained results, it is outlined how the total system load can be decreased by adopting some solar architecture techniques. The analysis of the auxiliary energy required by the solar combi system and the average solar fraction; shows the profitability of the SCS application in Algeria, especially in the case of low energy house. Furthermore, the economic aspect and the environmental impacts of the integrated solar heating system have been investigated. The equity payback and greenhouse gas 'GHG' emissions have been estimated by means of a numerical simulation using the powerful tools of the RETScreen free software program. The obtained results showed that the equity payback is strongly dependent on the fuel used by the conventional heating system. In the case, where the heating is assured by the gasoil, the equity payback is around the half of the project lifetime. From the environmental standpoint, the solar application is entirely advantageous. In addition, the natural gas is the most favourable conventional energy resource, with a minimum yearly GHG emissions compared to electricity and gasoil.

Controlling energy loss from roof structures equipped by round-corner double semi-hexagonal ferro- phase change material layer using magnetic field

Improving the thermal characteristics of building enclosures is a must in the context of rising global energy consumption. Heat losses through roof enclosures are one of the main causes of excessive energy consumption in the Heating, ventilation, and air conditioning systems in buildings. Designing novel roof structures to reduce heat losses is essential. The Phase Change Materials through their thermal properties can provide an effective passive solution in this regard. The present paper is dedicated to the analysis of a roof structure incorporating a Ferro-Phase Change Material enhanced with nanoparticles and subjected to an external magnetic field. The Ferro- Phase Change Material is placed in a round-corner semi-hexagonal block that can be oriented horizontally or vertically in the roof structure. The equations governing the heat and flow are developed and presented in the non-dimensional form. The set of equations were discretized and solve using control volume based finite element method. The effect of Hartmann number, the inclination of the magnetic field and the orientation of the Phase Change Material block on the flow and thermal behaviors of the Phase Change Material and on the thermal resistance of the roof structure are assessed. It is found that when the Ferro- Phase Change Material block is oriented vertically, it offers 30% less thermal resistance than the horizontal configuration in the absence of magnetic field. Increasing Hartmann number from 0 to 200 raises the thermal resistance by 80% for the vertical case and 45% for the horizontal case. Changing the inclination angle of the magnetic field has more effect on the Phase Change Material when its block is oriented vertically, with 30% faster melting and 45% decrease in the thermal resistance are found when the magnetic field is applied vertically instead of horizontally.

Development and evaluation of an energy-efficient intelligent infrared heating system for industrial buildings

Energy efficiency is a global problem that has become a top priority for all developed countries in recent years. Limited energy resources and high pollution worldwide have led to an increase in research and development in terms of energy efficiency. In the present work, one of the energy-efficient methods for heating by using infrared sources is focused. The advantages of infrared heaters compared to standard heating sources are underlined. A comparative study of the energy consumed during heating by the most frequently used by the heating systems has been made, and the results of the theoretically calculated power costs are presented. An intelligent system has been developed for the management of the infrared heaters to reduce the consumption of electricity better. The intelligent control system is based on a fuzzy-logic control and an internet of things. Results of simulation experiments of the intelligent system are presented as well as of the application of the system in a real environment. During the experiments, the system successes to control the heaters and to reduce power consumption. The achieved results prove that signal processing and control can improve the performance by using modern sensor systems, thereby additional efficiency can be achieved by using the infrared heating. It is possible to develop different optimization systems and algorithms for increasing the energy efficiency of different heating systems.

Implementation of Building a Thermal Model to Improve Energy Efficiency of the Central Heating System—A Case Study

This paper presents the concept of an innovative control of a central heating system in a multifamily building based on the original thermodynamic model, the resulting architecture of the control system, and the originally designed and manufactured wireless temperature sensors for thermal zones. The novelty of this solution is the developed layers of the control system: distributed measurement and correction analysis, which is based on the existing infrastructure and the local HVAC controller. This approach allows for the effective use of the measured temperature data from thermal zones and finally sending the value of the calculated correction of settings to the controller. Moreover, in the analytical layer, a model was also implemented that calculates the necessary amount of energy based on data from the subsystem of temperature sensors located in the thermal zones of the building. The use of the algorithmic strategy presented in this paper extends the functionality and significantly improves the energy efficiency of the existing, classic, reference heating control algorithm by implementing additional control loops. Additionally, it enables integration with demand-side response systems. The presented concept was successfully tested, achieving real energy savings for heating by 12%. These results are described in a case-study format. The authors believe that this concept can be used in other buildings and thus will have a positive impact on the energy savings used to maintain thermal comfort in buildings and significantly reduce CO2 emissions.

Performance assessment of a real water source heat pump within a hardware-in-the-loop (HIL) testing environment

Over the last decade, the global fight against climate change through electrification has led to an increase in research on building heating, ventilation, and air conditioning (HVAC) systems that utilize intelligent control algorithms to provide demand-side grid service while also maintaining the thermal comfort of building occupants. As the pivotal point between building electricity consumption and indoor thermal comfort, high-efficiency electrical vapor-compression heat pumps are at the center of these emerging studies, and various grid-interactive and occupant-comfort control algorithms have been developed for them. The impact of these algorithms on heat pump operation and performance when subjected to different weather conditions, building loads, and grid requests calls for investigation and verification via experimental testing with actual heat pumps integrated with real-time building and grid responses. This study introduces a Water-Source Heat Pump (WSHP) Hardware-in-The-Loop (HIL) Test Facility that is the first of its kind. This testbed utilizes a 2-ton variable speed water-to-air heat pump that is capable of interacting with a virtual environment currently comprised of an EnergyPlus (E+) building simulation, an agent-based occupant behavioral model, and a single U-tube ground-loop heat exchanger (GLHE) model. Detailed descriptions of the testbed’s physical design and operation, virtual environement, as well as their mutual communication is provided. An uncertainty analysis is also performed under manufacturer specified heating and cooling design conditions. This analysis shows that the total load across the WSHP’s demand side heat exchanger, i.e., the sum of its latent and sensible components, can be measured with a relative uncertainty of ± 10.4% and ± 3.6% in cooling and heating mode respectively. The WSHP’s coefficient of performance (COP) can be measured with relative uncertainties of ± 10.4% in cooling mode, and ± 3.7% in heating mode. A preliminary 24-h experimental demonstration is then performed utilizing the DOE prototype small commercial office building model in E+. The simulation takes place in Atlanta, GA on the date of 08/26/15 from 12:00 AM to 11:59 PM using TMY3 weather data. . The results from this demonstration show that over the course of this experiment the simulated outputs of zone dry-bulb temperature, zone humidity ratio, and WSHP inlet water temperature can be tracked by testbed emulators up to a root mean squared error (RMSE) of ± 0.27 °C, ± 0.376 g/kg, and ± 0.85 °C respectively. The WSHP’s dynamic behavioral characteristics and performance are also captured, and correspond well with the authors’ previous understanding of heat pump efficiency as a function of evaporator and condenser fluid inlet conditions respectively.

Evaluation of model predictive control (MPC) of solar thermal heating system with thermal energy storage for buildings with highly variable occupancy levels

The presence or absence of occupants in a building has a direct effect on its energy use, as it influences the operation of various building energy systems. Buildings with high occupancy variability, such as universities, where fluctuations occur throughout the day and across the year, can pose challenges in developing control strategies that aim to balance comfort and energy efficiency. This situation becomes even more complex when such buildings are integrated with renewable energy technologies, due to the inherently intermittent nature of these energy source. To promote widespread integration of renewable energy sources in such buildings, the adoption of advanced control strategies such as model predictive control (MPC) is imperative. However, the variable nature of occupancy patterns must be considered in its design. In response to this, the present study evaluates a price responsive MPC strategy for a solar thermal heating system integrated with thermal energy storage (TES) for buildings with high occupancy variability. The coupled system supplies the building heating through a low temperature underfloor heating system. A case study University building in Nottingham, UK was employed for evaluating the feasibility of the proposed heating system controlled by MPC strategy. The MPC controller aims to optimize the solar heating system’s operation by dynamically adjusting to forecasted weather, occupancy, and solar availability, balancing indoor comfort with energy efficiency. By effectively integrating with thermal energy storage, it maximizes solar energy utilization, reducing reliance on non-renewable sources and ultimately lowering energy costs. The developed model has undergone verification and validation process, utilizing both numerical simulations and experimental data. The result shows that the solar hot water system provided 63% heating energy in total for the case study classroom and saved more than half of the electricity cost compared with that of the original building heating system. The electricity cost saving has been confirmed resulting from the energy shifting from high price periods to medium to low price periods through both active and passive heating energy storages.

Байгалийн гамшигт үзэгдэл болох зудын үеийн боловсрол-судалгааны үр дүнгээс

Mongolia is one of the countries with the harshest climate in the world, with a short warm season lasting only two months and a long winter with temperatures below 35-40°C. Due to the severe winter and spring climate, heavy snowfall in the provinces and soums, the workload of herding families increases dramatically, and herders' children are engaged in animal husbandry because of everyday busy schedule. When herders experience severe weather conditions and heavy snowfall, the number of livestock reduce drastically, their family livelihood decreases, which negatively affect their psychological state, pay less attention to their children's schooling. In this article we analyzed the legal regulations on disasters and emergencies, we aimed to clarify secondary schools’ preparedness to the risks such as, drastic drop in attendance of students during natural disasters, failure of the heating system of school buildings and dormitories, cold classrooms, shortage of drinking water, etc.

Heating Ceiling System Efficiency in Different Climate Zones

Abstract There are many benefits of building construction with prefabricated thermo active ceilings technology, and the most highlighted are: short lead time, ease of installation, low price, lack of taking up space in a room and additionally the possibility of working in heating and/or cooling mode. An analysis was carried out to illustrate the factors that influence the thermal output of a ceiling heating system in residential buildings located in 5 climate zones in Poland and 2 in Ukraine. The thermal loads were determined for the entire building, designed in accordance with the regulations in force in each country, for the flats and particular rooms (considering the heat exchange between the flats according to PN-EN 12831:2006). An average heating medium temperature of 34°C was assumed. The results were compared with the achievable heating capacity of the ceiling system, which results from the difference between the heating medium temperature and the indoor room temperature. It was investigated that the system achieves the calculated output in all climate zones in Poland, while it will not be sufficient in Ukraine. This is due to both less stringent building thermal protection regulations and different indoor design temperature values, resulting in a higher average temperature in the flat. When analysed on a room-by-room basis, it became apparent that in all considered locations there were rooms for which the heating capacity was insufficient. In the climate zones I to IV in Poland, the problem concerns only bathrooms, where in this case quite often the surface heating can be combined with a supplementary electric radiator. In the V climate zone in Poland and both in Ukraine, the solution to the power shortage under design conditions may be: building construction according to a higher energy standard, increasing the supply temperature (with the limitation of maximum ceiling surface temperature to 35°C for living spaces) or using additional heating elements not only in bathrooms. A novel part of the article discusses calculated power shortages in relation to climate change and the external design temperatures suggested by sources other than the standard.

Privacy-Preserving Regulation Capacity Evaluation for HVAC Systems in Heterogeneous Buildings Based on Federated Learning and Transfer Learning

Heating, ventilation, and air conditioning (HVAC) systems in buildings have great potential to provide regulation capacity that is leveraged to maintain the balance of supply and demand in the power system. In order to make full use of HVAC’s regulation capacity, it is important to accurately evaluate it ahead of time. Because physical model-based approaches are hard to implement and highly personalized for each building, data-driven approaches are preferable for this capacity evaluation. However, given the insufficient data for individual buildings and buildings’ potential unwillingness to share their data because of privacy concerns, it is extremely challenging to build a high-performance data-driven regulation capacity evaluation model. In this paper, we propose a privacy-preserving framework that combines federated learning and transfer learning to evaluate the regulation capacity of HVAC systems in heterogeneous buildings. Specifically, a classified federated learning algorithm is proposed to build capacity evaluation models of HVAC systems for different building types. Each building trains its model locally without sharing data with other buildings to preserve privacy. The algorithm also tackles data insufficiency and achieves high evaluation accuracy. In addition, we design a cross-type transfer learning algorithm to enhance model generalization and further address data deficiency. A protocol is created for the above two algorithms to protect privacy and security. Finally, numerical case studies are conducted to validate the proposed framework.

Experimental Study of Photovoltaic-thermal Integrated Heat Pump Building Heating System

Photovoltaic-thermal (PV/T) systems and hydronic radiant floor heating systems can enhance energy efficiency and economic viability. This study investigates their integration through experimental research and designs an experiment to test their performance under typical winter conditions. The heat pump system achieves an average COP of 5.66 and an average photovoltaic power output of 107.5 W. The underfloor heating system quickly reaches and maintains 20.47°C with a water supply temperature of 50°C.

Integrated control of radiant floor heating systems in residential buildings

The ‘ideal’ optimal control of a radiant floor heating system (RFHS) can be achieved when a central controller is fully aware of the interrelationship between the different thermal dynamics of a boiler, radiant floor, and room. This study proposed integrated control strategies that can consider the interaction of heterogeneous RFHSs using a minimalistic approach with minimal data easily available from residential buildings. Three individual artificial neural networks were developed to choreograph the heterogeneous dynamics of the RFHSs for each household. Then, model predictive control was applied to realize the real-time integrated control of the RFHSs in the residential buildings. Approximately 14–46% of heating energy could be saved by integrated control. Moreover, the potential energy saving rate from integrated control varied depending on the degree of human intervention.

ВПРОВАДЖЕННЯ ЗАСОБІВ ДЛЯ ПОЗИЦІЙНОГО РЕГУЛЮВАННЯ ТЕПЛОСПОЖИВАННЯ

The article examines the scientific results of experimental studies of low energy efficiency of urban residential and communal energy supply. The purpose of the study is to reduce the costs of energy carriers in the field of housing and communal services using the example of residential, educational and industrial buildings of universities. Based on the analysis of the state of energy saving in the field of housing and communal services, a number of main factors influencing the reduction of its energy efficiency have been determined. Among the most important factors that require research is insufficient attention to the technical support of the energy consumption system, namely: outdated electrical equipment, low qualification of service personnel and an ineffective system of promotion of energy saving. According to the results of the conducted research, it was established that the degree of reduction of heat consumption in heating systems depends on heat losses due to the imperfection of factors that affect the reduction of energy efficiency, namely, the enclosing structures, which are determined by the thermophysical properties of the type and characteristics of heat energy meters, as well as through the control system, using which maintains optimal temperature values in building premises during the working day and their minimum permissible values in the evening hours, at night and on weekends. The results of the obtained research made it possible to state that in order to increase the energy efficiency of the heating system of buildings, it is necessary to provide a system of accounting and regulation of the consumption of the building coolant and to ensure the regulation of the coolant depending on the ambient temperature, as well as to limit heat consumption at night and on weekends (holidays). The installation of means of accounting and regulation of heat energy consumption, as well as the creation of a central information and measurement system with subsequent placement, make it possible to conduct operational monitoring of heat flows, which will contribute to reducing the amount of heat energy consumption by an average of up to 35%. Keywords: energy consumption, energy saving, energy efficiency, building, system, accounting, coolant, losses.

An integrated simulation of intermittent heating of multi-zone buildings by heat-pump heating systems with different terminal types

Intermittent heating has been considered to be an effective way to achieve energy savings compared with continuous heating. However, recent studies have found that actual energy savings from intermittent heating vary greatly, depending on actual building conditions, terminals and heating supply systems. For multi-zone buildings adopting heat pumps with specific terminals, a comprehensive analysis of energy savings resulting from intermittent heating still needs to be done. In the present study, an integrated dynamic model is developed by considering the interaction of thermal processes among building envelopes, terminals, and heat pumps. Its reliability is verified in field tests, and a better accuracy was achieved when considering the radiant heat ratio of terminals. On this basis, the model together with a source and terminal control strategy is applied to simulate the thermal behavior of heat pump heating systems for buildings under various conditions. The effect of different terminals and building envelopes on room temperature variation and energy utilization by intermittent heating is analyzed. The simulation results and practical projects indicate that heat pump power consumption under intermittent heating may be lower, close to or even higher than that under continuous heating. The factors that affect the efficient of intermittent heating, including building and system thermal inertia, heat pump operation COP, the radiant heat ratio of terminals, need to be systematically considered. Specifically, fan-coil heating systems could use 16.48% less energy, while radiant floor heating systems consume more energy under intermittent heating. Heat pumps under continuous heating are more efficient in buildings with radiative heating systems and heavy envelopes.

Multi-source-data state estimation for integrated electricity–heat-building networks

Building heating systems (BHS) play a major role in integrated electricity and heat systems (IEHS). To capture the real-time dynamic operating state of IEHS based on multi-source measurement data, this paper develops a comprehensive state estimation (SE) framework for IEHS with BHS fleets. First, a thermo-electrical SE model integrating BHS, electric power grid (EPG), and district heating network (DHN) is developed. Then, to jointly estimate the state variables of IEHS with different time scales of dynamics, a holistic SE algorithm is proposed based on the partial equivalence between the Weighted Least Squares (WLS) estimation problem and the correction stage of the Iterative Extended-Kalman Filter (IEKF). It also includes a data anomaly processing algorithm to combat data corruptions from sensing and communication processes. Simulation results show that the proposed framework can accurately track the thermo-electrical states of the system both in the presence of measurement noise and anomalies during various dynamics in IEHS.

Reconciling Airborne Disease Transmission Concerns with Energy Saving Requirements: The Potential of UV-C Pathogen Deactivation and Air Distribution Optimization

The COVID-19 pandemic caused a paradigm shift in our way of using heating, ventilation, and air-conditioning (HVAC) systems in buildings. In the early stages of the pandemic, it was indeed advised to reduce the reuse and thus the recirculation of indoor air to minimize the risk of contamination through inhalation of virus-laden aerosol particles emitted by humans when coughing, sneezing, speaking, or breathing. However, such recommendations are not compatible with energy saving requirements stemming from climate change and energy price increase concerns, especially in winter and summer when the fraction of outdoor air supplied to the building needs to be significantly heated or cooled down. In this experimental study, we aim at providing low-cost and low-energy solutions to modify the ventilation strategies currently used in many buildings to reduce the risk of respiratory disease transmission. Measurements of the indoor air bacterial concentration in a typical office building reveal that ultraviolet germicidal irradiation (UVGI) modules added to the HVAC system are very efficient at inactivating pathogens present in aerosols, leading to indoor concentrations as low as outdoor concentrations, even with significant indoor air recirculation. Moreover, measurements of the CO2 and aerosol air concentration reveal that, with air supply vents placed in the ceiling, placing the air exhaust vents near the floor instead of on the ceiling can improve the ventilation capacity in terms of effective flow rate, with significant consequences in terms of energy savings.

Thermal economy analysis and multi-objective optimization of a small CO2 transcritical pumped thermal electricity storage system

With expansion of application scale of distributed renewable energy, importance of researching small electricity storage system is increasing. Thermal economic performance of a small CO2 transcritical pumped thermal electricity storage system (SCT-PTES) is studied in this paper. NSGA-II optimization method and TOPSIS decision method are used to optimize system performance. This paper also proposes a small CO2 transcritical pumped thermal electricity storage coupled building heating system (STC-PTES-H) scheme. The system performance is also studied. Results show that: (a) When round-trip efficiency and LCOS of SCT-PTES are 26.93% and 0.3862 $/(kW·h), respectively, thermal economic performance is optimal. (b) When amount of electricity produced by renewable energy sources is 10 MW, LCOS of SCT-PTES is 0.2002$/(kW·h). (c) Correlation between thermodynamic performance and economic performance of system is fitted, and optimization time is reduced. It provides a theoretical basis for optimization of thermal economic performance of system. (d) Energy utilization of SCT-PTES-H can reach 97.66%. It makes better use of energy. This research provides technical support for application of SCT-PTES in distributed renewable energy power plants.

A mixed integer linear programming-based simple method for optimizing the design and operation of space heating and domestic hot water hybrid systems in residential buildings

The hybridization of energy systems is based on the combined integration of both renewable and non-renewable technologies and thermal energy storage. These hybrid installations improve cost effectiveness and energy efficiency when they are correctly designed and the operation strategy is suitable. Despite the relevance of achieving the optimal configuration, sizing and control strategy of hybrid thermal systems, there is no simple and generic methodology which allows this type of installations to be optimized in the project phase. In response to this issue, in this work, a mixed integer linear programming-based simple model is carried out with the aim of obtaining the optimal design, sizing and operation of thermal energy systems in residential buildings. To do so, a superstructure is defined that includes the main technologies commercialized for thermal energy systems in buildings. Technical, economic, environmental and legal constraints are determined in the proposed generic model. In order to validate the method, it is applied to a central space heating and domestic hot water installation of a residential building located in a cold climate in Spain. Optimal solutions are obtained considering three different perspectives —economic, environmental and multicriteria— and are compared to the current installation. According to the results, the overall cost of the economic optimal configuration is reduced by 15%, whereas the greenhouse gas emissions decrease by 56% in the environmental optimal solution. It is thus demonstrated that the proposed generic and simple model is a useful tool for determining the optimal hybridization of the plant and for analysing the technical, economic and environmental feasibility of these systems in the project phase.

Daytime Radiative Cooling: A Perspective toward Urban Heat Island Mitigation.

Traditional cooling and heating systems in residential buildings account for more than 15% of global electricity consumption and 10% of global emissions of greenhouse gases. Daytime radiative cooling (DRC) is an emerging passive cooling technology that has garnered significant interest in recent years due to its high cooling capability. It is expected to play a pivotal role in improving indoor and outdoor urban environments by mitigating surface and air temperatures while decreasing relevant energy demand. Yet, DRC is in its infancy, and thus several challenges need to be addressed to establish its efficient wide-scale application into the built environment. In this Perspective, we critically discuss the strategies and progress in materials development to achieve DRC and highlight the challenges and future paths to pave the way for real-life applications. Advances in nanofabrication in combination with the establishment of uniform experimental protocols, both in the laboratory/field and through simulations, are expected to drive economic increases in DRC.