Heating System Research Articles

Optimization and preparation for the start-up of the plasma ICR heating system at the KTM tokamak

The paper presents and discusses the results of the research on the preparation of the HF plasma heating system of the KTM tokamak for the start-up. The calculations have been performed to determine the parameters at which the most effective absorption of the HF radiation by the plasma of the KTM tokamak was expected, the results of measurements of the frequency response of the antenna-feeder device of the HF heating system generator of the KTM tokamak plasma have been presented. The result of the carried out work have shown that more efficient plasma heating on a KTM tokamak can be obtained at a frequency of 14 MHz.

Energy and economic analysis of energy efficiency actions in surgery rooms: A dynamic analysis

This research proposes several measures designed for reducing the primary energy consumption of operating rooms, but at the same time complying with the stringent regulations governing operating rooms. In particular, this study proposes a novel control strategy for the air handling unit serving the surgery rooms, along with two innovative layouts designed for decreasing the thermal energy demand. Note that the two proposed novel layout involves the adoption of a round-around-coil and a recovery heat pump, in order to recover the waste heat of the air stream leaving the user. The simulation model of the operating room and of its heat, ventilation, and air conditioning systems plant are developed using the TRNSYS18 environment. The performance of the air handling unit and heat pumps are calibrated against the manufactured data. The case study consists of a real surgery theatre including three operating rooms. This facility is located in Naples, south of Italy. The operating room is served by a dedicated air handling unit, integrated with a heat pump providing heating and cooling energy, as well as a humidifier. All proposed layouts demonstrated high performance, reducing primary energy consumption by roughly 22–26%, with a simple payback period lower than one year. All the proposed layouts are able to significantly reduce the specific primary energy consumption of the selected operating rooms. In fact, the specific energy consumption decreases from 1.883 kWh/m2 to 1.452–1.383 kWh/m2.

Preparation and characterization of innovative cement mortar incorporating fatty acid/expanded graphite composite phase change material for thermal energy storage

To explore the application of phase change energy storage materials in building energy conservation, in this study, an innovative composite thermal energy storage cement mortar (CTESCM) was developed using lauric acid–palmitic acid/expanded graphite (LA-PA/EG) as the composite phase change material (CPCM). Seven different CTESCM test blocks with different CPCM mass contents were prepared. The thermal characterization of the CTESCMs was achieved using a differential scanning calorimeter (DSC), a thermogravimetric analysis (TGA), thermal conductivity tests, and heat storage/release tests. The physical behavior was assessed using density, mechanical performance was assessed using compressive strength, and the microstructure was observed using a scanning electron microscope (SEM). The results indicate that the phase transition temperature of the CTESCMs was lower than that of the LA-PA/EG CPCM, and the latent heat consistently decreased with the decrease of the CPCM mass content. With the addition of the CPCM, which had a low-density porous structure, the thermal conductivity, density, and compressive strength of the CTESCMs decreased. CTESCM with a mass fraction of 20%C (20% cement) CPCM can be used for building energy conservation such as floor radiation heating systems.

Research on Low-Carbon Design and Energy Efficiency by Harnessing Indigenous Resources through BIM-Ecotect Analysis in Hot Climates

In the face of contemporary challenges, such as economic instability, environmental degradation, and the urgent global warming crisis, the imperative of sustainability and energy efficiency has reached unparalleled significance. Sustainability encompasses not only the natural environment, but also extends to our immediate surroundings, including the built structures and the communities they serve. Embracing this comprehensive perspective, we embarked on a mission to conceive and construct a model house that harnesses state-of-the-art energy-efficient technologies. Our goal was to seamlessly integrate these features not only to meet our sustainability objectives, but also to mitigate environmental threats.This model embodies a harmonious fusion of indigenous resources, employing locally sourced stone and employing traditional construction techniques. Through this approach, we achieved significant reductions in carbon emissions and established a framework for passive cooling and heating systems. Moreover, the design is intrinsically attuned to its contextual surroundings, preserving the diverse tapestry of regional architectural styles. This study stands as a testament to the potential of innovative design and technology in shaping a sustainable future. The research employs a multi-dimensional approach, encompassing strategies of architectural design with a traditional planning approach, sustainable material selection, energy efficiency, and life cycle assessment across a diverse set of case studies. Building energy analysis is conducted through the application of BIM (Ecotect), providing insights into how BIM can adapt and thrive in various environments. Key findings underscore that thermal performance, minimizing energy loads, and reducing carbon emissions are pivotal aspects in designating a building as both green and energy efficient.

Strategic Evaluation of Sustainable Practices for HVAC Systems in Small and Medium-Sized U.S. Manufacturers

Abstract This paper investigates the often overlooked yet crucial role of Heating, Ventilation, and Air Conditioning (HVAC) systems in advancing sustainable manufacturing practices in the United States. Through all outcomes of the energy assessments conducted by the Industrial Assessment Centers (IACs) in various industrial settings, the current study focuses on the energy consumption of HVAC systems and assesses the impact of their energy-efficient measures on the overall industrial energy usage. In-depth analysis covers both technological and economic facets of resource management practices, utilizing case studies and data from energy assessments on 20,818 small- and medium-sized manufacturing facilities. The results reveal substantial potential for reducing energy consumption, estimated at 71.9 million MMBtu per year, along with annual energy cost savings of approximately $744 million per year and a noteworthy mitigation of 8.7 million metric tons of CO2 emissions per year, all achievable through HVAC system improvements. These findings show the practical significance of sustainable HVAC practices and their potential to improve energy efficiency and mitigate the environmental impact within the manufacturing sector.

The Effect of Radiation Intensity on the Performance of Direct-Expansion Solar PVT Heat Pump Systems

The objective of this study was to investigate the impact of solar radiation intensity on the performance of direct-expansion solar PVT heat pump systems. To this end, an experimental setup was constructed for direct-expansion photovoltaic (PVT) solar heat pump water heating systems and photovoltaic (PV) power generation systems. The system performance and main parameters were analyzed and discussed under different solar radiation intensities. The winter experiments in southern China revealed that the exhaust temperature of the heat pump unit varied considerably under clear conditions, while the back temperature remained stable, fluctuating between approximately −13.5 °C and 24 °C. In contrast, the power generation of PVT panels increased with the increase in radiation intensity, from 78.33 W to 122.68 W, for an increase of 56.6%. Furthermore, the total electricity generation of the PVT panels was higher than that of PV panels, with an increase of 8.7–8.3%. Nevertheless, discrepancies between experimental and theoretical data were observed, particularly under overcast conditions, where the back panel temperature error was pronounced. Additionally, the system exhibited enhanced stability at elevated temperatures in comparable environments, accompanied by an improvement in the system’s coefficient of performance (COP) by 5.67%.

Greenhouse gas mitigation potential through clean energy for cement production in India

Abstract A preliminary approach has been made to assess the concentrated solar energy applications in cement production as well as greenhouse gas mitigation potential. The work starts with identification of processes that utilizes thermal energy in cement production. Then cluster of cement plants located at different locations of the country has been made. Also, the availability of solar radiation and wind speed at each plant location have been identified. Subsequently, the solar industrial process heating system have been developed for different locations in the country. Further, solar reactor output, number of heliostats, total land area and mirror surface have been estimated. All these estimations are done by considering three types of thermal losses in solar reactor i.e. 15, 30 and 45 percent respectively. Solar energy can provide a total of 738.11 PJ of thermal energy, which is needed to fulfil the process heating requirement of the calcination process for the manufacturing of cement in India. Solar industrial process heating system for cement production in India can reduce yearly CO2 emissions by 2457-7648 thousand tonnes.

Development of a Prototype Hydraulic Damping Device for Hot Water Heating Circuit in Pulse Mode

This paper provides a comprehensive exploration into the design and implementation of the hydraulic damping device within a pulse mode hot water heating loop. It outlines a systematic approach aimed at optimizing system performance, detailing the operational principles of the pulse mode heating circuit and presenting a structured construction scheme for the hydraulic damping apparatus. Accompanying this analysis is a simplified diagram illustrating the hydraulic damping system, offering a clear visual representation of its integration within the heating circuit. Through mathematical transformations, essential parameters such as complex impedance, frequency function, and vibration frequency characteristics are derived, providing valuable insights into the dynamic behavior of the system. Culminating this investigation, the paper constructs the frequency response of the circuit, offering a comprehensive understanding of its dynamic behavior across varying frequencies. This synthesis of theoretical frameworks and practical applications advances our understanding of pulse mode hot water heating technology, paving the way for enhanced efficiency and performance in heating systems.

Sizing of storage‐based renewable off‐grid system according to supply of electrical and thermal energies considering unscented transformation‐based stochastic optimization: A case study

AbstractThe paper presents the planning (sizing) of a hybrid islanded system containing only renewable sources including wind turbines, photovoltaics, and bio‐waste energy units for the simultaneous supply of electrical and thermal energy. The mentioned renewable sources are used to supply electrical energy. The bio‐waste unit (BEU) is equipped with combined electrical and thermal technology. It is used along with heat pumps to supply thermal energy. Electrical and thermal storage are employed to make the renewable power output as close as possible to the demand level. Electric storage can be either stationary (e.g., battery) or mobile (e.g., electric vehicles), but thermal storage is as stationary type of storage. In the following, the proposed scheme minimizes construction and maintenance costs imposed by power sources, storage devices, and power electronic converters, and expected storage degradation cost. This plan is bound to the model of operation of sources, storage devices, and power electronic converters. In this model, renewables are the main source of power to supply consumers, where storage is adopted to increase the generation level to make it as close as possible to the demand curve. The uncertain parameters are imposed by the load, renewable phenomena, and mobile storage parameters. To model these uncertainties, stochastic optimization based on unscented transformation is used. Finally, the findings of the paper demonstrate that the suggested scheme succeeds in the economic planning of the system with a simultaneous supply of electrical and thermal energy. The BEU equipped with a combined electricity and heat system along with thermal storage and a heat pump to supply thermal load besides providing electric energy can reduce the planning cost by 2.9% compared with the case with only electrical energy. Also, the mobile storage presence in the hybrid system can reduce the number of stationary storage devices, which alone results in a 7.7% decrease in the planning cost of the hybrid system.

Thermodynamic and Economic Analyses of a Novel Cooling, Heating and Power Tri-Generation System with Carbon Capture

The combined cooling, heating, and power (CCHP) system has attracted increasing attention due to its potential outstanding performance in thermodynamics, economics, and the environment. However, the conventional CCHP systems are carbon-intensive. To solve this issue, a low-carbon-emission CCHP system (LC-CCHP) is firstly proposed in this work by integrating a sorption-enhanced steam methane reforming (SE-SMR) process. In the LC-CCHP system, CO2 is continuously captured by the calcium loop so that low-carbon energy can be generated. Then, the LC-CCHP system thermodynamic model, mainly consisting of a dual fluidized bed reactor which includes the SE-SMR reactor and a CaCO3 calcination reactor, a hydrogen gas turbine, a CO2 reheater, and a lithium bromide absorption chiller, is built. To prove that the LC-CCHP model is reliable, the system major sub-unit model predictions are compared against data from the literature in terms of thermodynamics and economics. Finally, the effects of reforming temperature (Tref), the steam-to-carbon mole ratio (S/C), the calcium-to-carbon mole ratio (RCC), the equivalent ratio for gas turbine (RAE), and the hydrogen separation ratio (Sfg) on total energy efficiency (ηten), total exergy efficiency (ηtex), and carbon capture capability (Rcm) are detected. It is found that the minimum exergy efficiency of 64.5% exists at the calciner unit, while the maximum exergy efficiency of 78.7% appears at the gas turbine unit. The maximum energy efficiency and coefficient of performance of the absorption chiller are 0.52 and 1.33, respectively. When Tref=600 °C, S/C=4.0, RCC=7.62, RAE=1.20, and Sfg=0.27, the ηten, ηtex, and Rcm of the system can be ~61%, ~68%, and ~96%, and the average specific cost of the system is 0.024 USD/kWh, which is advanced compared with the parallel CCHP systems.

Energy Potential of Existing Reversible Air-to-Air Heat Pumps for Residential Heating

Heat pumps can be considered one of the key technologies to meet the building stock decarbonization target set by Europe. Especially in warm locations, many households have already incurred costs for the installation of air-to-air heat pumps, but, in most cases, they only use them in summer for cooling, while heating is provided by fuel-fired boilers. For these households, the goal of reducing primary energy consumption could be achieved almost cost-free by using heat pumps, that were installed for summer cooling, also for winter heating. Based on this assumption, this research aimed to evaluate the energy savings and environmental benefits that can be achieved by using air-to-air heat pumps instead of gas boilers as the main heating system, without additional costs except for the installation of electric radiators in bathrooms. To quantify variations in energy, environmental, and economic savings compared to the baseline condition, detailed simulations were conducted with the dynamic hourly calculation method (EN ISO 52016) in six different European locations, considering heat pumps with different efficiencies and two different building types. The analysis showed positive impacts at all sites due to the use of heat pumps, which can lead to primary energy savings ranging from about 20% to about 60%. The results varied according to outdoor climate, coefficient of performance of heat pumps, building type, and, on the economic side, the cost of energy. This research provides useful results for outlining decarbonization scenarios, assuming that heat pumps are one of the technologies needed to meet the EU’s climate neutrality goal.

Integrating energy simulations and analytical hierarchy process procedure in multi-criteria evaluation of heating systems for industrial buildings

Industrial buildings in Italy are generally aged and widely outdated from an architectural, technological, and environmental perspective. Despite the current limitations affecting both envelope and system installations, enhancement strategies are not frequently debated in the literature or addressed recurring to not adequately comprehensive approaches. This research examines space heating options for integrated retrofit interventions of manufacturing facilities using a novel methodology that combines multi-criteria decision analysis based on the Analytic Hierarchy Process (AHP) with building energy simulations. Interviews with representatives from medium-sized companies in Tuscany provide insights into the exigencies of industrial buildings, while on-site surveys identify common features of industrial buildings in the region leading to the identification of a representative case study building. This facility is examined producing several energy models to account for the different heating system alternatives to be evaluated according to criteria including economic, environmental, comfort, space, and reliability. Both qualitative judgments and quantitative outputs from energy simulations are considered to rank the technological alternatives encompassed in the analysis. In addition, sensitivity analyses are carried out to highlight the impact of boundary conditions on optimal configuration selection. Economic considerations weigh heavily for industrial owners, often outweighing environmental concerns due to higher initial investment requirements for low-impact solutions. Consequently, gas boiler generators and hot-water fan heaters emerge as preferred options for their flexibility, low initial cost, and ease of installation.

Integrating PEM fuel cell control with building heating systems: A comprehensive thermal and control model analysis

Integrating PEM fuel cell control with building heating systems: A comprehensive thermal and control model analysis

Observation of alpha-particles in recent D–T experiments on JET

The fusion reaction between deuterium and tritium, D(T,n)4 He is the main source of energy in future thermonuclear reactors. Alpha-particles (4 He-ions) born with an average energy of 3.5 MeV transferring energy to the thermal plasma during their slowing down, should provide the self-sustained D–T plasma burn. The adequate confinement of α-particles is essential to provide efficient heating of the bulk plasma and steady burning of a reactor plasma. That is why the fusion-born α-particle studies have been a priority task in the second D–T experiments (DTE2) on the Joint European Torus (JET) to understand the main mechanisms of their slowing down, redistribution and losses and to develop optimal plasma scenarios. JET with Be-wall and W-divertor, enhanced auxiliary heating systems and improved energetic-particle diagnostic capabilities, producing significant population of α-particles, provided the possibility for comprehensive studying of the α-particle behaviour. Selected results of the confined and lost α-particle measurements, evidence of α-particle self-heating and assessments of the fusion performance are presented in this paper giving an opportunity for further modelling and extrapolation to the International Thermonuclear Experimental Reactor and burning plasma reactors.

Booster heat pump with drop-in zeotropic mixtures applied in ultra-low temperature district heating system

The pursuit of sustainable district heating solutions has driven a growing interest in ultra-low temperature district heating (ULTDH) systems, where booster heat pumps (BHPs) play a pivotal role despite challenges posed by their efficiency limitations under large temperature glide conditions. This paper investigates the potential of drop-in R-1234yf/R-32 zeotropic mixtures in BHPs compared to a baseline R-134a system, within the context of a ULTDH framework. This study focused on the viability of the mixtures of R-1234yf/R-32 with the composition ratio of 80 %/20 % and 90 %/10 %. The investigation reveals disparities in compressor efficiency and heat exchanger pressure drop at the component level. Device-level analysis unveils increased COP for R-1234yf/R-32 mixtures, alongside with maximum second-law efficiencies reaching 0.32. A remarkable enhancement in heating capacity up to 58 % was found. System-level analysis demonstrated exergetic efficiencies and identified preferable district heating temperatures. Exergetic efficiencies of 0.47, 0.55, and 0.59 were achieved for domestic hot water preparation at district heating supply temperatures of 30 °C, 35 °C, and 40 °C, with a subsequent shift in optimal district heating temperatures as central heating station efficiency decreased. Temperature profile analysis underscored challenges stemming from excessive subcooling, highlighting the need for configuration refinements.

Solar energy utilization for underfloor heating system in residential buildings

In this paper, the thermal performance of a solar energy system for heating a residential building is experimentally investigated. In this system, the solar thermal energy is supplied via a flat plate solar collector that provides the heated water into a small-scale chamber, that represents the residential building. The experimental setup is installed in Jouf University campus (Latitude: 29° 47′ 1.9” N, Longitude: 40° 2′ 42.2” E) located at Al-Jouf Province, Saudi Arabia. In this experiment, the hot water supplied from solar collector is mixed with water in the storage tank, then extracted from bottom of the tank to be circulated in a copper tube loop located underneath the floor tiles of the chamber and hence increases the chamber’s air temperature. Two circulation pumps are installed in the system, one to circulate the water between solar collector and storage tank and the other to circulate the water between storage tank and chamber. Measurements of several parameters were conducted to evaluate the overall thermal efficiency of the system. The experimental results showed an average efficiency of 51 %, when operating the system for eight-hours duration in the winter season. Additionally, an economic assessment was carried out to confirm the system’s feasibility. This assessment demonstrated that the constructed system is economically feasible, with an estimated benefit-cost ratio of 1.42.

The effect of the electron κ-distribution on the dust particle charging in the Radio-frequency thermal-sheaths

Abstract In order to investigate collisionless radiofrequency plasma sheaths
containing dust particles, three models are utilized:
the novel kinetic scheme. Ensemble-in-Spacetime (EST) model for calculating sheath parameters, the Dust
Particle Charging model, and the Single Dust Particle model. The EST model has
been modified to account for κ-electron distributions.
This model is applicable to radiofrequency plasma sheaths found in tokamaks equipped with an ion cyclotron
radiofrequency (ICRF) wave heating system, such as JET, West(Tore Supra), EAST,
ASDEX-U, and KSTAR. The calculated sheath parameters are utilized to determine
the electron and ion currents of the dust particles. In the intermediate radio-frequency
regime, when the ion plasma frequency is comparable to the ICRF, the flux and energy
of the ions are modulated in time within the sheath. The ions are not inertialess, and
the value of κ affects the electron and ion densities.
As the value of κ increases, the time-averaged electron and ion densities, sheath edge position, and area of the
sheath voltage-sheath charge hysteresis loop also increase. However, the ion energy
distribution remains insensitive to the κ distribution. The dust particles are charged
with different negative charges based on their radius, position within the sheath, κ-
electron distribution, and sheath potential. These particles exhibit oscillatory motion
due to their interactions with the plasma and gravitational fields and are accelerated
toward the plasma core.

Experimental and Numerical Study of Newly Assembled Lightweight Radiant Floor Heating System

In this study, the heating capacity of a new prefabricated assembled hot water radiant modular heating system made from a recycled waste building masonry structure is investigated through experimental and numerical simulation methods. The heating capacity of the system in different working conditions (a water supply temperature of 48 °C, 51 °C, 56 °C, and 61 °C; a flow rate of 0.49 m3/h, 0.35 m3/h, and 0.21 m3/h) is analyzed and verified. A three-dimensional steady-state heat transfer numerical model of the floor heat transfer of the module is established, and the accuracy of the model is verified through the measured results to investigate the heating capacity of this system under different water supply temperatures, flow rates and coil spacings. The results show that the new prefabricated hot water radiant module heating system has a 0.9 °C higher air temperature and 2.1 °C higher average floor surface temperature than the traditional wet floor radiant heating system under the same experimental conditions, and the response time is 44% shorter. The water supply temperature can significantly change the heating capacity of the system, while the water supply flow rate has little effect on the system. The established three-dimensional steady-state numerical model can be in good agreement with the measured results. This study can provide an experimental and theoretical basis for the design and application of such systems.

Investigation of the Temperature Distribution and Energy Consumption of an Integrated Carbon Fiber Paper-Embedded Electric-Heated Floor

This study examined spatial and temporal thermal performance and energy consumption. The temperature distribution in the running period was monitored in test rooms with integrated electric- and hot water-heated floors. The short- and long-term energy consumption of the two heating systems were recorded and compared. The results indicated that the integrated electric heating system generated higher temperatures for indoor air and on the exterior surface of the wooden floor than the hot water heating system; meanwhile, the difference in the mean temperatures of the exterior and rear surfaces of the electric-heated floor was 2.44 °C, while that of the hot water-heated test room was 13.25 °C. The efficient structure of the integrated electric heating system saved 22.97% energy compared to the hot water system after short-term (7 h) charging and reaching a dynamic balance, and it efficiently increased the energy utilization rate to 11.81%. After long-term charging, the daily energy consumption of the integrated electric heating system consumed much less energy than the hot water system every month. The integrated electric heating system saved 62.55% and 34.30% of energy in May and January, respectively, and consumed less than half of the energy the hot water system consumed in the less cold months. Therefore, a high-efficiency and energy-saving integrated electric-heated floor could be a potential indoor heating solution.

Investigation of the Temperature Distribution and Energy Consumption of an Integrated Carbon Fiber Paper-Embedded Electric-Heated Floor

This study examined spatial and temporal thermal performance and energy consumption. The temperature distribution in the running period was monitored in test rooms with integrated electric- and hot water-heated floors. The short- and long-term energy consumption of the two heating systems were recorded and compared. The results indicated that the integrated electric heating system generated higher temperatures for indoor air and on the exterior surface of the wooden floor than the hot water heating system; meanwhile, the difference in the mean temperatures of the exterior and rear surfaces of the electric-heated floor was 2.44 °C, while that of the hot water-heated test room was 13.25 °C. The efficient structure of the integrated electric heating system saved 22.97% energy compared to the hot water system after short-term (7 h) charging and reaching a dynamic balance, and it efficiently increased the energy utilization rate to 11.81%. After long-term charging, the daily energy consumption of the integrated electric heating system consumed much less energy than the hot water system every month. The integrated electric heating system saved 62.55% and 34.30% of energy in May and January, respectively, and consumed less than half of the energy the hot water system consumed in the less cold months. Therefore, a high-efficiency and energy-saving integrated electric-heated floor could be a potential indoor heating solution.