Heat Consumption Research Articles

ENERGY MANAGEMENT SYSTEM (EMS) AS A TOOL IN LIMITING THE COAL TRACE IN INDUSTRY

Increasing energy efficiency will be crucial to achieving the climate goals laid out in European Uniondirectives. This is particularly true for industries whose share of heat and energy consumption,with Poland as an example, is about one-third of the total. This challenge entails implicationsboth for the reduction of greenhouse gas emissions, especially CO2, and for maintaining thecompetitiveness of EU industry on the global market. This article presents the basic principlesand application of an Energy Management System – EMS – in industrial processes, together withthe monitoring of Key Energy Performance Indicators – KPIs – as a tool for making informedinvestment decisions to improve the energy efficiency of companies and industrial processes. Anattempt is made to present the situation in Poland in terms of the energy situation, with a focus onthe automotive industry as an example.

Energy performance of buildings with multi-ribbed composite wall structural system

Multifunctional multi-ribbed composite wall (MRCW) structural system has been increasingly used due to its dual load bearing and energy saving capacities. Most of existing studies were focused on its mechanical properties. This paper aims to evaluate its energy saving effect. To this end, two models are constructed using EnergyPlus for the same residential building in Beijing, China, but with different systems of MRCW and shear wall. The dynamic simulation of hourly energy consumption throughout one year is carried out at the building operation stage. The results show that the heating energy consumption is higher than the cooling energy consumption. The total energy consumption of the MRCW system can be reduced by 11.4 % compared with that of the shear wall system. Further, the annual energy consumption of the residential building models in five typical climate regions in China with different orientations is simulated. The results show that the energy saving of MRCW system range from 5 % to 13 % in the five regions when compared with shear wall system, and the absolute value of energy saving is the largest in severe cold and cold regions. The north-south orientation is the best energy-saving orientation. Based on this study, it can be concluded that, other than carrying load, MRCW system can also save energy compared with shear wall system, especially in severe cold and cold regions.

Research on the air-infiltration rate shelter coefficient of building complexes based on building parameter clustering

The configuration of a building complex can significantly influence the air-infiltration rate, which subsequently affects the energy consumption for heating and cooling. Given the diversity of parameters associated with a building complex, it is challenging to study all combinations. This study proposed the k-means clustering method to identify representative building clusters, thereby facilitating the derivation of correction coefficient for the air-infiltration rate within a complex. Initially, data pertaining to district characteristics, such as the complex density, height, and building aspect ratio, were collected and clustered to obtain several representative groups of building clusters. Subsequently, a validated computational fluid dynamics program with the renormalization group (RNG) k–ε turbulence model was employed to investigate the spatial characteristics of the pressure coefficient (Cp) on building surfaces across various groups within the complex. Finally, the shelter coefficient (SAIR), which represents the ratio of an individual building to those in different groups, was determined to correct for the air-infiltration rate in diverse district types. The results show that SAIR varies considerably (from 0.15 to 0.53) owing to the different densities, heights, and layouts between buildings. The applicability of SAIR was further demonstrated and verified in a case study of a building in Dalian, China. The research results can provide a method for predicting the air-infiltration rate of building complex.

Urban microclimate prediction based on weather station data and artificial neural network

Urban microclimate has a significant impact on building energy consumption. Building energy modeling (BEM) requires accurate local weather conditions near a target building, whereas Typical Meteorological Year (TMY) weather inputs often use remote airport weather data. An artificial neural network (ANN) model is presented in this study to predict urban microclimates based on long-term measurements from local weather stations near urban buildings and their significance in analyzing building energy consumption. By utilizing only a few months of data, the ANN model could connect local and remote meteorological parameters for a whole year. The 20-year historical weather data at the airport was then used to generate a local TMY. Based on the original and local TMYs, this study compared building heating and cooling loads. This method was evaluated for five weather stations within the city of Montreal to assess the impact of the local microclimate on the energy consumption of buildings. Based on locations, urban microclimate contributed to an additional 2 % to 14 % cooling energy consumption and a reduction of 1 % to 10 % winter heating energy consumption.

An exergy-ecology assessment method and its application for basic building heating schemes

ABSTRACT Building heating is the main type of heating consumption in China. At present, there is a lack of attention given to the assessment of ecological cost or impact considering energy depreciation for various heating schemes. In this work, a method of exergy-ecology assessment is proposed to evaluate the energy and ecological characteristics of four basic building heating schemes. The solar-equivalent joule was adopted as the unified quantitative value of ecological impact by converting exergy, material, and cost flows. The exergy-ecology balance was established for each scheme, and a series of indexes were proposed and calculated through two strategies. The results show that the objective exergy efficiency of Scheme 3 heat pump is the highest (53.87%) and that of Scheme 2 electric heater is the lowest (17.58%). Larger difference of energy grade between energy providing side (0.83 for gas fuel and 1 for electricity) and receiving side (0.18 for output water) connects with lower exergy efficiency. Scheme 3 heat pump has the highest eco-exergy efficiency under both assessment strategies (71.89% and 53.86%), followed by Schemes 4 solar collector (61.52% and 36.34%). This method proves that the thermodynamics perfectness of system is positively correlated with ecological sustainability and can be used to assess other energy systems.

Case study: reducing heating energy consumption in a high tunnel greenhouse with renewable energy and microclimate control by bench-top root-zone heating, bench covers, and under-bench insulation

Appalachian State University's Nexus project designed an efficient greenhouse heating system that integrated renewable energy and root zone heating technology to reduce the greenhouse heating energy burden on local farmers and installed it at local cooperative farms. This study analyzed 5 years of data from 2018 to 2022 to investigate the energy savings and microclimate control effectiveness of the Nexus heating system installed at Springhouse Farm in North Carolina, USA. By varying bench cover materials, bottom insulation, and the number of loops of root zone tubing, the different soil temperatures required for plant types and growth stages were achieved with a single temperature controller. A root zone heating fluid of 32.2 ℃ satisfactorily maintained the germination soil between 20 and 25 ℃ in March 2019 with an average outside temperature of 4.8 ℃ and an average low temperature of − 0.4 ℃. Growing soil maintained an average temperature of 15 ℃ with bottom insulation and an average of 11–12 ℃ without bottom insulation. Compared to the conventional heating system (a forced-air propane unit heater alone), weather-adjusted propane consumption (propane usage divided by heating degree days) was reduced by 65% with the Nexus system alone and 45% with the Nexus system and unit heater together. It shows that the Nexus system has significantly reduced greenhouse heating energy consumption and maintained productive conditions. The renewable energy fraction ranged only 9–13% of the total thermal energy used due to the high inlet temperature entering the solar thermal collector. This can be improved by separating the heat storage and backup heat source.

A living lab to develop smart home services for the residential welfare of older adults

Owing to the decline in the physical and social functions of older adults, the residential environment substantially impacts the psychological and emotional stability and life satisfaction for older adults. Recently, there has been a growing interest in providing residential welfare services related to the health and independent living of the older adults. The primary objective of this research was to identify the needs and perceptions of older adults regarding smart home services and associated sensors and evaluate the indoor environment conditions of older adults through a living lab. Survey results indicate that older adults felt the burden of electricity bills in summer and winter and had relatively high safety-related smart home service needs. Focus group interviews with the participants in the living lab confirmed that older adults positively perceived the benefits and privacy of the living-lab sensors. In addition, the analysis of indoor environment data over one year from a case study household showed that approximately 66.4 % during the winter season and 13.1 % during the summer season have fallen within the neutral thermal comfort range according to the proposed approach (i.e., predicted mean vote (PMV) calculated using heart rate). This study adopted the proposed PMV method (hereafter PMV-P) that takes into account personal factors (e.g., metabolic rate of older adults that can be calculated using heart rate) and environmental factors (e.g., temperature, humidity) by using the real-time data collected from IoT (Internet of Things)-based sensors. Furthermore, this study proposed a new home energy management system (EMS) algorithm on the basis of model predictive control for reducing heating energy consumption while satisfying the thermal comfort. The new EMS was demonstrated to achieve 5–12 % heating energy savings depending on the thermal comfort preferences of occupants. Overall, the results of multidisciplinary research not only provided the preliminary evidence regarding the needs and perceptions of older adults toward IoT-based sensors but also showcased the development of IoT-based smart home service system through the living lab.

Analysis of Internal Conditions and Energy Consumption during Winter in an Apartment Located in a Tenement Building in Poland

The residential sector of existing buildings has great potential in energy savings and the improvement of indoor conditions. The modernization of buildings is of particular concern to the policies of the European Union, local governments, and building users. The aim of this paper is to present an analysis of indoor parameters and energy consumption for heating for an apartment located in a pre-war tenement building before and after thermomodernization. The analysis was conducted for winter conditions and was based on measurements and simulations. Originally, the building had not undergone any thermomodernization actions since its reconstruction after WWII. Interior, exterior, and surface temperatures were recorded to describe the thermal conditions of the apartment, while gas meter readings were used to estimate energy consumption for heating purposes. WUFI Plus software (v.3.2.0.1) was used to estimate energy consumption and perform energy simulations for the apartment over an extended period of time. The best thermomodernization effect resulted from the replacement of windows and the inefficient heating system, avoiding surface condensation and reducing final energy consumption by more than 50%. The extended options resulted in energy savings higher than 70%. The presented analysis shows the importance of retrofit measures and proves that even a small improvement can bring significant benefits.

Woven Agarose-Cellulose Composite Aerogel Fibers with Outstanding Radial Elasticity for Personal Thermal Management.

Aerogel fibers are good thermal insulators, suitable for weaving, and show potential as the next generation of intelligent textiles that can effectively reduce heat consumption for personal thermal management. However, the production of continuous aerogel fibers from biomass with sufficient strength and radial elasticity remains a significant challenge. Herein, continuous gel fibers were produced via wet spinning using agarose (AG) as the matrix, 2,2,2,6,6-tetramethylpiperidine-1-oxyl radical-oxidized cellulose nanofibers (TOCNs) as the reinforcing agent, and no other chemical additives by utilizing the gelling properties of AG. Supercritical drying and chemical vapor deposition (CVD) were then used to produce hydrophobic AG-TOCN aerogel fibers (HATAFs). During CVD, the HATAF gel skeleton was covered with an isostructural silica coating. Consequently, the HATAFs can recover from radial compression under 60% strain. Moreover, the HATAFs have low densities (≤0.14 g cm-3), high porosities (≥91.8%), high specific surface areas (≥188 m2 g-1), moderate tensile strengths (≤1.75 MPa), excellent hydrophobicity (water contact angles of >130°), and good thermal insulating properties at different temperatures. Thus, HATAFs are expected to become a new generation of materials for efficient personal thermal management.

Occupant-centric dynamic heating demand in residential buildings based on a temporal-spatial combined quantification method

The occupant-centric Part-Time-Local-Space heating mode holds paramount significance for the carbon neutralization of buildings in China. It ensures a harmonious match between heat supply and personal demand in both temporal and spatial dimensions, effectively reducing space heating consumption. However, current studies predominantly focus on the temporal-spatial heating demands of occupants at the room scale, but the zonal scale heating demands remain inadequately explored. Thus, we developed a temporal-spatial combined quantification method to analyze residents’ indoor movement characteristics. It aims to identify the localized subzones in a room where residents have prolonged stays, with spatial boundaries of subzones entirely defined based on high-resolution positioning data. Using this approach, we analyzed the temporal-spatial heating demands of four households under single- and multiple-resident scenarios in typical rooms. Furthermore, we discussed the differences in demand between different heating modes. Results revealed distinctive “local space” demand features in living room and “part time” demand features in dining room. The areas of sofa subzones generally occupied less than 15 % of a room (within 4 m2), and stay durations in dining-table subzones ranged from 0.3 h to 1.2 h. Considering the entire monitored rooms, residents occupied only 4.1–12.1 % in space with 10.7–47.9 % in time per day, highlighting the significant energy-saving potential of the occupant-centric Part-Time-Local-Space heating mode. This evaluation provides a reference for the design and implementation of personalized environmental control system.

Toward sustainable heating: Assessment of the carbon mitigation potential from residential heating in northern rural China

Reducing carbon emissions from residential heating has become a global priority due to the urgency of mitigating climate change. In rural areas, there is a tension between the heavy reliance on traditional energy and the necessity for revitalization. Therefore, conducting a comprehensive assessment of heating energy consumption and carbon reduction potential is crucial. This study utilized a bottom-up statistical model to examine energy dynamics in northern rural China based on large-scale household surveys (n = 6150 rural households from 15 provinces) conducted between 2012 and 2017. Heating energy consumption was estimated to reach 175–275 Mtce in 2030 and 137–245 Mtce in 2050, and related carbon emissions were 466–736 million tons and 318–574 million tons, respectively. Furthermore, by implementing solid policies, including improving poorly installed building envelopes, enhancing renewable energy, promoting heat pumps adoption, and encouraging occupants' green behavior, carbon emissions can be reduced by 41.2%–76.2%. This study's findings offer governments valuable insights into strategies for reducing carbon emissions.

Pathways to mitigate household carbon emissions in Chinese cities: Intentions, actions, and environments

Cities represent primary origins of carbon emissions and key spaces to cope with climate change. Low-carbon city pilots (LCP) have carried out three groups to mitigate household carbon emissions in China. There are many difficulties in identifying possible sources and factors of household carbon emissions. This study attempted to construct the analytical framework to examine potential mitigation pathways, which would influence household carbon emissions. Collecting data from urban energy consumption, the difference-in-differences model, a widely utilized quantitative method, is employed to assess the policy effect of LCP on mitigating household carbon emissions in China. Results indicated that: (1) LCP could mitigate household carbon emissions (−7.6%) and per capita household carbon emissions (−8.8%), which passed serious robustness tests. (2) Potential mechanisms, through which LCP mitigate household carbon emissions, were recognized, in terms of subjective intentions, objective actions, and external environments. (3) Policy effects in eastern and central cities were significantly negative.The improvement of energy consumption for winter heating in northern cities could mitigate more household carbon emissions.

Integrated heat dissipation mechanism design of electronic equipment cabinet based on flow and sound analysis

The electronic equipment cabinet is the main bearing platform of radar back equipment, normally using a forced convection cooling form. With the continuous increase of radar function and processing capacity, the total heat consumption of electronic equipment is getting higher and higher, and the fan speed is constantly increasing. Besides the noise of electronic equipment cabinet shows a trend of gradually increasing. To reduce cabinet noise from the source, this paper presents three structural forms of integrated heat dissipation mechanism, and uses FloEFD fluid heat transfer analysis software and COMSOL acoustic module to analyze the cabinet flow field and the cabinet sound field respectively. By comparing the cabinet noise characteristics under different structural forms, the analysis results show that the noise reduction effect of bilateral air duct structure is best.

A multi-objective optimization of a single-phase immersion cooling system at cabinet level

With the rapid development and urgent requirement of high computing power, the energy consumption of data center (DC) is constantly increasing. The issue of high energy consumption constrains rapid development of DCs and becomes a major challenge that urgently needs to be solved in the transformation of DCs towards large-scale, intelligent, and energy-saving. In the present study, a cabinet level single-phase immersion cooling (SPIC) system was experimentally investigated with coolant of Noah 3000D. The cooling capacity and energy consumption level of the SPIC system were investigated. The impacts of the heat load, coolant flow rate, and cooling water flow rate on the thermal performance of the SPIC unit were quantitatively analyzed. Based on experimental data fitting, the heat transfer criterion correlation and pressure difference calculation formula were obtained. The error caused by the heat transfer criterion correlation and pressure difference calculation formula is basically within ± 5 %. Based on the multi-objective optimization, both the coolant flow rate and cooling water flow rate cause obvious influences on the heat transfer coefficient and energy consumption of SPIC systems. The temperature changes on both sides of the heat exchanger can be ignored, and the error caused by the assumption does not exceed ± 1 %. With some valuable findings obtained, this work can supply some technique references for engineering design and operation management of SPIC systems.

Design of proactive management system for residential buildings by using smart equipment

This study's object is an energy efficiency of residential sector. The work is aimed at solving the task to improve the energy efficiency of the housing sector by devising technical solutions for monitoring and managing energy consumption and microclimate parameters of buildings. The proposed proactive management system for residential buildings consists of multi-sensors measuring CO2, temperature and humidity, smart meters of heat and electricity consumption, and smart plugs. The equipment is combined into single system through an integration controller with remote user access through an interactive web interface. A feature of the technical solution is the ability to collect, process, visualize, and archive data on the consumption of energy, as well as on the key parameters of the microclimate of residential premises. The advantages of the system are its flexibility due to the possibility of integrating additional devices during operation, as well as the use of standard communication protocols, which enables the interchangeability of component elements. The implementation and testing were carried out under the conditions of a real pilot site. The use of the system in practice confirmed the efficiency and stability of the operation, making it possible to obtain data on the parameters of energy consumption and microclimate and devising recommendations for reducing energy consumption at the pilot site. It was established that the microclimate meets the requirements of the standards (air temperature is about 22 °С while relative humidity does not exceed 60 %). Decrease in energy consumption can be achieved by reducing the temperature of the heat carrier in the absence of residents, as well as by considering the influence of weather conditions. During periods of residents activity, an excess of the permissible level of CO2 was recorded, therefore, automatic ventilation systems should be provided in the apartments

Effect of structural improvement of gaskets on the heat leakage load and energy consumption of the refrigerator

Gaskets play a significant role in the thermal insulation of refrigerators. Previous studies mainly focused on how to obtain the heat and moisture transfer load of a given gasket, but lacked appropriate structural improvement measures and their effect on the heat leakage load and energy consumption of refrigerators. In this paper, the heat transfer analysis of an original gasket was conducted via numerical simulation. It was found that the main thermal insulation weaknesses of the original gasket are gasket-cold air, gasket-outer shell of the cabinet, gasket-inner lining of door and gasket-hot air. Thus, adding an auxiliary-airbag to the original gasket and a comprehensive new-design gasket were proposed to improve the thermal insulation. Compared with the original gasket, the numerical simulation results showed the heat leakage loads of the auxiliary-airbag and new-design gasket were reduced by 18.44 % and 27.49 %. The total heat leakage loads of refrigerators equipped with improved gaskets were reduced by 4.46 % and 6.64 %. The effect of two structurally improved gaskets on the refrigerator energy consumption was experimentally studied. The repetitively measured results showed the energy consumption of refrigerators with the auxiliary-airbag and the new-designed gasket were reduced by 0.93 % and 3.19 %. The reason why the reduction in refrigerator energy consumption is lower than the reduction in heat leakage load is due to the difficulty in achieving the designed assembly state of the gasket during actual installation. Based on the holdings of refrigerators around the world, it is estimated that the refrigerators energy consumption can be reduced by 106.776 billion kWh per year and carbon emissions can be reduced by 12.74 million tons per year when using the new-design gasket proposed in this study.

Multi-Objective Optimization for Winter Heating Retrofit in Rural Houses of Cold Regions: A Case Study in the Wusu Area

In regions of China experiencing severe cold, the duration of the winter heating season significantly contributes to elevated heating energy consumption in rural dwellings. This study focuses on typical brick-and-concrete rural homes in the Wusu area. Utilizing the Rhino–Grasshopper parametric modeling platform, it aims to minimize heating-related carbon emissions and the overall costs associated with retrofitting. The approach involves improving the insulation properties of the building envelope to reduce energy requirements. Additionally, the study incorporates solar photovoltaic systems atop rural homes, building upon low-carbon, passive, energy-efficient design principles. By examining the influence of various factors on rural housing energy consumption, the research employs the entropy weight method to identify the most effective design solutions. The goal is to explore strategies for the energy-efficient retrofitting of rural dwellings in areas faced with harsh winter conditions, aligning with the objectives and preferences of Applied Sciences. The simulation results reveal the following: (1). In comparison with the baseline scenario, 42.2% of the optimized solutions within the Pareto frontier satisfy the current standards for 75% energy savings in energy-efficient residential design. (2). The lowest recorded thermal consumption index for the buildings can reach 12.427 W/m2, at which point the rate of energy savings is elevated to 79.5%. (3). Within the solutions identified by the Pareto frontier, 80% exhibit initial investments that are lower than the cost savings over the lifecycle due to reduced energy consumption (dCg < 0), demonstrating the economic feasibility of the proposed retrofitting strategies.

СРАВНИТЕЛЬНАЯ ОЦЕНКА СХЕМ ПЛАВНОГО РЕГУЛИРОВАНИЯ МОЩНОСТИ ГАЗОГОРЕЛОЧНОГО УСТРОЙСТВА

Large-scale gasification of agricultural enterprises, personal subsidiary plots and farms, for which the most energy-intensive processes are the preparation of feed, food, and home heating, has revealed the need to automate digesters. The peculiarity of the operation of digesters is due to the fact that as the contents of the cooking container are heated to boiling temperature, the heat consumption decreases, and when the product boils, the heat consumption drops below 10%. It has been established that the lack of automatic gas control leads to excessive heat release into the atmosphere during the combustion of gaseous fuel. Previously, a gas burner unit was developed based on a partially automatic industrially produced gas burner device of the AGU-T-M type for digesters, which makes it possible to regulate gas flow in proportion to the consumed heat flow. The task was set to develop a promising scheme that would make it possible to regulate the gas flow in the digester in proportion to the consumed heat flow. This article describes two variants of schemes for proportional control of gas flow in a digester: the first is an improved scheme based on an automated gas burner device of the AGU-T-M type; the second is a circuit developed on the basis of Peltier semiconductor modules, a control solenoid with a gate valve. An assessment is given indicating the advantages and disadvantages of these schemes. It is shown that the first scheme is efficient and energy-independent; its use is most effective in remote settlements where there are frequent interruptions in the centralized power supply. The second scheme corresponds to the latest achievements of scientific and technological progress.

New Afton Mine diesel and battery electric load-haul-dump vehicle field test: Heat and dust contribution study

ABSTRACT The New Afton Mine and CanmetMINING conducted a joint study to better understand the environmental and performance impacts of battery- and diesel-powered mobile equipment. The two main objectives were to: (1) determine if battery electric and diesel load-haul-dump vehicles (LHDs) could perform equivalent duties, and (2) gather environmental information for determining the ventilation airflow requirements for battery-powered vehicles. The study focused on the effects of the LHDs on heat and dust generation and energy consumption in a ramp and in a production level. For the production environment tested, respirable crystalline silica concentrations were the driver to assess the battery-powered LHD airflow volume. The potential to reduce this volume was identified in the controlled air streams and conditions tested. However, it depended on the scenario and the dust generation and suppression mechanisms. One scenario evaluated environmental conditions under a reduced airflow (50% less than the diesel LHD). For this mine site, area contaminants levels exceeded limits; therefore, the potential for savings was less than 50%. For the scenarios tested, the battery electric and diesel LHDs were able to move equivalent amounts of material in a similar time.

Occupant behavioral adjustments and thermal comfort with torso and/or foot warming in two cold indoor environments

Personal warming systems have been shown to improve occupant thermal comfort in cold indoor environments. Currently, there are almost no published comprehensive studies on the examination of occupant behavioral patterns in relation to the use of personal warming systems. Thus, this study presented a human trial study to investigate the effects of torso and foot warming on thermal comfort of young female occupants in two cold indoor environments (15 °C and 17 °C), based on a water warming suit (WWS) and HYB (a WWS combined with heated socks). Besides, occupant behavior adjustments regarding water temperature setpoints for WWS and electrical heating levels for heated socks were thoroughly investigated. WWS and HYB improved occupant thermal comfort at 15 °C and 17 °C, with ≥85.7 % of ‘No Change’ OTPVs (overall thermal preference votes) observed during the last 20 min of exposure. Foot heating can significantly reduce heating demand on the upper torso, both in terms of water setting temperatures and total heating time. HYB exhibited a 25.4 % and 43.3 % shorter total duration with water setting temperatures of ≥40 °C compared to WWS at 15 °C and 17 °C, respectively. Further, occupants have employed a trial-and-error adjustment approach to determine the heating temperature/level that offers optimal thermal comfort in the cold. Lastly, the use of two PWS combinations has the potential to reduce energy consumption for indoor heating by 62.9 %, 32.1 %, and 53.7 % in cities such as San Francisco, Phoenix, and Minneapolis (baseline heating setpoint: 21.5 °C).