Water Heating Energy Research Articles

Design and Analysis of a Solar-Powered Water Heating System

Water heaters consume a large amount of electricity for heating water. Traditional heaters require heating coils to heat up water using a minimum of 2000 Watts for the process. Well, when we use solar energy for water heating it requires around 30 to 50 Watts of power thus saving more a lot of energy. We here developed a more efficient solar water heater to heat up water at a faster rate using efficient coiling along with heat trapping and reflecting mirrors. The water heater can more efficiently heat up water at a faster pace than traditional solar water heaters. The system makes use of steel pipes coiled together for passing water through them. The pipes are heated by solar rays directly falling on them. We additionally use an aluminium plate behind the pipes to absorb the rays passing through in between pipes. Over this we use 2 additional reflective sheets to gather and reflect additional solar rays over the pipes. This system heats up the pipes thus heating up the water passing

Exploring the theoretical minimum energy use in the U.S. office building sector

This paper explores the minimum energy that would be required to provide all energy-using services currently used the U.S. office building sector if they were all provided by thermodynamically ideal devices that do not violate physical law. Data from the U.S. DOE and the General Services Administration were used to identify office building workspace services, equipment, occupancy and schedules. Internal building loads were estimated after identifying or conservatively approximating the thermodynamically ideal power required for each service. The average thermodynamically ideal office building in the U.S. would use 2.2 kWh/m2-yr or less, which represents 1.0% of the current average end-use consumption in the sector. Such a large gap between the thermodynamic limit and today’s practice is related to the fact that the energy performance of all the internal gain producing equipment in buildings is far from ideal along with the HVAC equipment and envelope components. Ideal office buildings would use 69.7% of their energy for cooking and related domestic water heating and cooling; illumination accounts for a smaller portion, consuming 17.5%, while office equipment and cooling would use 6.9% and 5.9% of the total consumption, respectively. Dramatic reductions come from the elimination of heating energy and air distribution energy brought about by ideal adiabatic building envelopes and frictionless air distribution. Cooling energy is virtually eliminated by the combination of greatly reduced cooling loads and ideal Carnot equipment. But the thermodynamically ideal office equipment would use two orders of magnitude less energy than today as well.

Fabricated of Photovoltaic Thermal System with Phase Change Material

At present, solar energy is widely recognized as one of the primary sources of renewable energy. Nonetheless, conventional solar photovoltaic (PV) panels suffer a significant decrease in efficiency when exposed to extreme temperatures, making them unsuitable for long-term operation. To address these limitations, hybrid photovoltaic thermal (PVT) systems with phase change materials (PCM) have emerged as sophisticated solutions, leveraging thermal energy for water heating and PCM for thermal energy storage. This work aims to evaluate key economic parameters of fabricated PVT system (with and without PCM) against commercial solar water heaters and electric heaters, using metrics such as payback period and annual worth. The calculations are carried out using Microsoft Excel spreadsheets. The results reveal that the payback period for PVT systems, both with and without PCM, exceeds 25 years, primarily due to the high initial costs associated with PVT technology. In contrast, solar water heaters and electric water heaters offer shorter payback periods. Specifically, after 25 years, the annual worth for the fabricated PVT system is MYR 923.12. Essentially, the economic analysis suggests that the PVT system has a longer operational lifetime than solar water heaters and electric heaters, despite the extended payback period. This economic analysis has the potential to encourage the large-scale fabrication and installation of efficient PVT-PCM systems. It provides consumers with a viable alternative to consider installing PVT and PVT-PCM systems instead of PV and solar thermal systems separately. Additionally, this study contributes to reducing carbon emissions and advancing the Sustainable Development Goals (SDGs).

Cooling and heating innovations: exploring the diverse applications of heat pumps

Heat pumps are versatile and energy efficient devices that play a crucial role in modern heating, cooling, and refrigeration applications. This paper provides a concise overview of the diverse applications and benefits of heat pumps across residential, commercial, industrial, and transportation sectors. The paper discusses the principles of heat pump operation, emphasizing their capability to transfer heat from one location to another using thermodynamic processes. The work highlights key applications such as residential heating, ventilation, and air conditioning systems, commercial refrigeration, hot water heating, process cooling, and renewable energy integration. The energy efficiency and environmental benefits of heat pumps are also emphasized, showcasing their potential to reduce carbon emissions and contribute to sustainable energy practices. By understanding the broad scope of heat pump applications outlined in this work, researchers, engineers, policymakers, and industry stakeholders can gain insights into the significance of heat pump technology in advancing energy efficiency and addressing climate change challenges.

Enhancing frameworks for utilising Sankey diagrams in modelling the water-energy nexus and circularity

Understanding the connection between water supply and energy consumption in a circular economy is crucial for managing the demands of these resources. Sankey diagrams have the potential to enhance the visualisation of resource flows. However, there is a knowledge gap regarding the effective use of Sankey diagrams to capture the water-energy nexus and circularity of water. This study focused on effectively utilizing Sankey diagrams to model the nexus of water and energy flows and to assess the circularity of water. A comprehensive literature review was conducted on major studies on water material flows and modelling. This was supported by a review of approaches for modelling circularity, which have evolved from the material circularity index. The newly developed framework in this paper models water resource flows at all stages of the water supply chain, embedding the nexus as an interaction and considering resource intensity and material circularity index at each node. A city-level case study in South Africa was then used to apply the recommendations, model circularity, and the water-energy nexus using Sankey diagrams. In terms of circularity, the results indicate that water loss in the study area was very high, accounting for up to 40% of the total water supply and the water recycle rate was still very low, ranging from 3% to 7%. In terms of the nexus, the residential sector was found to have the highest energy intensity for water supply, primarily due to energy demand for water heating. Exploring the use of renewable or solar energy for water heating will be of interest and value. The new approach presented in this study allows for the simultaneous consideration of objectives, enabling a more robust analysis of energy-effective water use and water circularity along the water supply chain.

Heating and Cooling with Renewable Energy from Wastewater

Energy from wastewater is recognized as a renewable energy source and can add a valuable contribution to the EU’s path to decarbonization. With modern heat exchangers and heat pumps, buildings and districts can be supplied with energy for heating, cooling and water heating. Based on the successful results of the implementation in Vienna Blumental, another project in Vienna has been rolled out: The Vio Plaza building complex will be supplied with energy from wastewater for heating (1.2 MW) and cooling (6 MW). This article presents the case study at Vio Plaza, gives a detail description of the system design and delivers first-hand information about operation of the installed system. Special focus is put on the innovative monitoring system and resulting monitoring data, which prove the good operation of the system. Based on these results, further knowledge about these systems will be gained to support the increasing implementation of this technology.

A Comprehensive Review of the Thermohydraulic Improvement Potentials in Solar Air Heaters through an Energy and Exergy Analysis

Supply disruptions, uncertainty, and unprecedented price rises of fossil fuels due to the recent pandemic and war have highlighted the importance of using renewable sources to meet energy demands. Solar air collectors (SACs) are major types of solar energy systems that can be utilized for space and water heating, drying, and thermal energy storage. Although there is sufficient documentation on the thermal analyses of SACs, no comprehensive reviews of the exergetic performance or qualitative insight on heat conversion are available. The primary objective of this article is to provide a comprehensive review on the optimum conditions at which the thermal performance of diverse types of solar air collectors is optimized. The effect of operating parameters such as temperature rise, flow rate, geometric parameters, solar radiation, and the Reynolds number on the thermal performance of SACs in terms of thermal hydraulic performance, energy, and exergy efficiencies has been reviewed adaptively. Beyond the operating parameters, a deep investigation is outlined to monitor fluid dynamics using analytical and computational fluid dynamics (CFDs) methodologies in the technology of SACs. In the third phase, thermodynamic irreversibility due to optical losses, thermal losses between absorber and environment, heat losses due to insulation, edge losses, and entropy generation are reported and discussed, which serve as the fundamental tools for optimization purposes.

A Systematic Review of the Potential Influence of Urbanization on the Regional Thunderstorm Process and Lightning Activity

In the context of global climate change, lightning disasters have emerged as a serious environmental factor that restricts the sustainable development of megacities. This paper provides a review of the research on the impact of urbanization on thunderstorm processes and lightning activity, exploring various aspects, such as aerosols, urban thermal effects, urban dynamic effects, and building morphology. Despite numerous significant achievements in the study of the impact of air pollutants on lightning activity, there is no consensus on whether aerosols serve to enhance or inhibit lightning activity. The temperature difference between the urban underlying surface and the natural underlying surface could sustain and promote the occurrence and development of convective systems, thus enhancing lightning activity. In terms of urban dynamics, the barrier effect has led to the maximum center of lightning appearing at the edge of a built-up area, which might be associated with factors, such as urban heat island (UHI) intensity, wind speed, synoptic background, and city size. Additionally, the size of a city and the height of the buildings was also an influencing factor on lightning activity. In summary, scholars have made progress in understanding the characteristics and drivers of urban lightning activity in recent years, but there are still some urgent problems that need to be solved: (1) How to analyze, comprehensively, the spatiotemporal patterns of urban lightning activity under different thunderstorm intensity backgrounds? (2) How to conduct analysis to investigate the influence of alterations in the boundary layer structure, water–heat energy balance, and water vapor circulation processes on urban lightning activity in the context of urbanization? (3) How to couple numerical models of different scales to enhance the understanding of the impact of complex underlying surfaces on urban lightning activity? Future studies could investigate the relationship between urbanization and thunderstorm/lightning activity using a combination of observational data, numerical modeling, and laboratory experiments, which holds promise for providing valuable theoretical insights and technical support to enhance the prediction, nowcasting, early warning, and risk assessment of thunderstorms and lightning in urban areas.

Construction and Comparison of the Efficiency of Water Heating Systems using low Cost Solar Collectors

This work describes the manufacture of two solar water heating (SWH) systems, one using polyvinyl chloride (PVC) pipes and the other using PVC plates, both with approximately the same area of collecting solar thermal energy. The aim is to analyze their efficiencies and discuss physical concepts and their practical applications. Both SWH collectors were placed side by side under the sun, such that they were submitted to the same climatic conditions. This work also draws attention to the importance of using solar radiation1 as an alternative and sustainable source of energy for water heating.

Peer-to-peer energy trading for demand response of residential smart electric storage water heaters

Environmental concerns and emission reduction targets are driving a transition from fossil fuel to renewable-based electricity generation. However, intermittent and distributed renewable generation brings challenges for the grid operation, as the low voltage distribution grid increasingly becomes constrained during high residential solar PV generation. The electrification of water heating presents a large opportunity to address this challenge by intelligently responding to electrical network conditions. Smart water heaters with thermal storage can soak up excess PV as a thermal battery, which facilitates maximum renewable generation and solves local grid problems. However, the centralized operation of electricity markets tends to impede the benefits of the localized distributed energy resources (DER). In such a scenario, peer-to-peer (P2P) energy trading allows neighbouring prosumers to trade energy between themselves with minimum interference from electricity grid operators. This research develops a P2P energy trading framework, using advanced, multi-zone electric storage water heaters with autonomous and aggregated control. The financial benefits identified in this research are forthcoming due to new participation in the electricity market ancillary services, demand management and P2P energy trading. Simulated results have identified that up to 92% of household water heating energy can originate from their own rooftop PV. At the electricity grid level, P2P energy trading demonstrates an increase in the aggregated PV self-consumption from 39% to 83%, importantly allowing the remaining 17% to target grid support in periods of supply shortfall. Average retail consumer energy savings of AUD$369/annum are identified, which include 17% of savings that are attributed to P2P energy transactions, delivering a capital payback of <3 years.

Detailed evaluation of electric demand load shifting potential of heat pump water heaters in a hot humid climate

Heat pump water heaters (HPWH) are a proven method of reducing water heating energy use over prevailing electric resistance systems (ERWH). Both technologies lend themselves to enhanced control for peak load reduction. Laboratory tests were conducted in Central Florida using the CTA-2045 standard to evaluate load shifting strategies with connected water heaters. Four HPWHs from three manufacturers, including two different tank volumes, were tested alongside an ERWH in a garage-like environment. Tests aimed to shift energy use away from utility peak load periods to off-peak times when excess renewable energy resources are often available. Two load-shifting strategies were shown effective, Shed and Critical Peak, with variation by manufacturer. Beyond draw volume, other factors influenced HPWH load shifting: Florida winter conditions, which increase the energy used per draw, provided the greatest challenges to complete load shift. Inlet water temperature had a large impact on the success of load reduction. Ground temperatures in which water pipes were buried largely determined inlet water temperatures. HPWH efficiency setting: Heat pump water heaters often default to a “hybrid” mode that may use some electric resistance heat to minimize risk of running out of hot water. Operational mode can impact load shifting potential.

Investigating the annual energy-saving and energy-output behaviors of a novel liquid-flow window with spectral regulation of ATO nanofluids

Building envelopes with energy-generation from renewable sources are highly promising for the green development of buildings. Recently, a new concept of energy-efficient window i.e., the water flow window (WFW), that can capture solar energy for domestic water heating, was reported. However, the output heating capacity of the WFW is inferior due to the limited absorption bandwidth of water. In this study, the ATO-based liquid filled window (LFW) was newly conceived for broadband solar harvesting and effective indoor solar regulation, and then a transient model was developed to figure out the annual performance of ATO-based LFW. By comparing the performance of ATO-based LFW with different ATO concentrations, it was found that an ATO mass fraction of 100 ppm is a positive solution for feasible luminous transmittance about 52%, and excellent monthly output heating capacity between 19 and 60 MJ/(m2·month) in Beijing. With the 100 ppm ATO-based LFW nanofluids, the output heating capacity and the annual solar heat gain coefficient (SHGC) of the ATO-based LFW in four cities with different climatic conditions were discussed. The results indicate that the 100 ppm ATO-based LFW shows the highest level of output thermal energy in Hong Kong, the highest output water temperature in Beijing, the lowest output heating capacity in Harbin, and the lowest cooling energy-saving potential in Chengdu. We believe that the ATO-based LFW is a feasible and applicable solution for achieving carbon neutrality in buildings, especially for buildings in hot regions.

Theoretical Evaluation of Photovoltaic Thermal Water Source Heat Pump, Application Potential and Policy Implications: Evidence from Yangtze River Economic Belt, China

In the context of carbon neutrality, making full use of renewable energy is the key to further improve China’s development index. Within China’s Yangtze River Economic Belt, solar energy and river water, as clean and abundant sources of renewable energy, have garnered increasing. In this paper, a solar energy and surface water driven cogeneration system model is developed by TRNSYS to provide users with heat, cold and electricity. Six representative cities located along the upper, middle, and lower reaches of the Yangtze River Economic Belt were selected to evaluate and analyze the energy-saving, emission reducing, and economic and environmental benefits of solar energy and river water heat utilization in the aspects of energy, economy, and environment. The results shows that the annual power output of PV/T-GSHP system, from the west to the east of the Yangtze River, shows a phase growth trend, which is related to the light intensity. The annual heat output of PV/T plate gradually decreases from the lower reaches of the Yangtze River to the upper reaches. The research findings confirm the application potential of new energy sources in the Yangtze River Economic Belt and quantify the emission reduction effects of new environmental protection actions such as solar energy and river water heat sources. It provides valuable guidance for the utilization of new energy sources, including solar energy and surface water heat energy in the Yangtze River Economic Belt, as well as for optimizing energy policies.

Multidimensional Indicator of Energy Poverty in South Africa Using the Fuzzy Set Approach

The electricity supply in South Africa is characterized by load-shedding. This study analyzed the determinants of the multidimensional energy poverty index (MEPI) in South Africa. The data, which were taken from the 2019–2021 General Household Survey (GHS), were analyzed using Tobit regression. The results showed that between 2019 and 2021, the use of clean energy for cooking declined from 85.97% to 85.68%, respectively, whereas the use of clean energy for water heating declined from 87.24% in 2020 to 86.55% in 2021. Space heating with clean energy declined from 53.57% in 2019 to 50.35% in 2021. The average fuzzy MEPI was 0.143 and Western Cape and KwaZulu-Natal provinces had the highest average values with 0.180 and 0.176, respectively. In the combined dataset, the Tobit regression results showed that, compared to Western Cape, the fuzzy MEPI significantly decreased (p &lt; 0.01) by −0.038, 0.028, 0.045, 0.023, 0.029, 0.038, 0.037, and 0.042 for residents in Eastern Cape, Northern Cape, Free State, Kwazulu-Natal, North West, Gauteng, Mpumalanga, and Limpopo provinces, respectively. In addition, the fuzzy MEPI for the Black, Coloured, Asian, and White respondents decreased by 0.042, 0.062, and 0.084, respectively. The fuzzy MEPI for male-headed households and the number of social grants increased, whereas the fuzzy MEPI significantly decreased (p &lt; 0.01) for the monthly salary and age of household heads. It was concluded that energy poverty in South Africa manifests through unclean energy utilization for space heating. The promotion of clean energy utilization should focus on deprived provinces, farms, and tribal areas.

Solar Hot Water Systems Using Latent Heat Thermal Energy Storage: Perspectives and Challenges

Domestic water heating accounts for 15% to 27% of the total energy consumption in buildings in Australia. Over the past two decades, the latent heat thermal energy storage (LHTES) system has been widely investigated as a way to reduce fossil fuel consumption and increase the share of renewable energy in solar water heating. However, the research has concentrated on the geometric optimisation of the LHTES heat exchanger for the past few years, and this might not be sufficient for commercialisation. Moreover, recent review papers mainly discussed the development of a particular heat-transfer improvement technique. This paper presents perspectives on various solar hot water systems using LHTES to shift focus to on-demand performance studies, as well as structure optimisation studies for faster commercialisation. Future challenges are also discussed. Since the topic is an active area of research, this paper focuses on references that showcase the overall performance of LHTES-assisted solar hot water systems and cannot include all published work in the discussion. This perspective paper provides directional insights to researchers for developing an energy-efficient solar hot water system using LHTES.

Fabrication of Parabolic-trough concentration for solar water heating

This paper presents the design fabrication Parabolic-trough solar water heating is a well-proven technology that directly substitutes renewable energy for conventional energy in water heating. In Two meters parabolic solar concentration has been fabricated to produce boiled water up to 100oC for the purpose of central heating services. The concentration is toward the sun light during the day time; by using a control circuit, The amount of the portable water was much dependent on the accurate focusing of the system which increases according to preheating. This system could therefore be used for heating water at home via increasing the temperature in hot tank by covering the hot water and isolating the tank from the surroundings.

Carbon footprint: IPCC targets vs. building and social standards

Residential buildings in Russia consume electricity, natural gas, thermal energy for home and water heating, as well as other resources from external suppliers. Such resource consumption results in direct and indirect carbon dioxide emissions that affect the environment. Sustainable development requires the humanity to fit the environmental carrying capacity, and measures against climate change require carbon emissions to reduce. This paper compares carbon footprint reduction target declared by UNCC Conference 2015 and the Paris Agreement, as well as targets offered by other environmental institutions, to carbon emissions arising from existing Russian building standards and social norms application, and actual data. Building standards set the amount of heat per square meter to be delivered to apartment buildings depending on its geographic location, while social norms set a minimal premises area per resident. Also social standards for electricity and natural gas consumption per person exist. Russian Government decrees regulate utility services parameters for apartment and residential buildings, setting hot water temperature and consumption standards per resident and for common household needs. These norms and standards permit the minimal carbon dioxide emissions per year per resident to assess and compare to the carbon footprint reduction target. This paper demonstrates that existing Russian building standards and norms result in carbon emissions per capita significantly exceeding the targets, and recommends standards and norms update to reduce carbon footprint, admitting at the same time that such update is only a step towards the Paris Agreement targets.

Utilization of Solar Energy for Water Desalination and Purification Using Solar Concentrator

This paper focuses on a a solar energy-based project aimed at water desalination and purification. The project's objective is to establish an economically viable and sustainable approach to water heating and desalination, offering benefits to global communities. The project team has devised a solar heating system utilizing a Fresnel array-inspired setup, intended to complement a desalination system employing membrane distillation, which necessitates water heating. The primary focus has been on designing an efficient solar receiver to absorb solar energy for water heating. Moreover, the team has developed equations for concentrator mirror angles across various days, generating charts indicating optimal mirror angles and spacing between mirror rows for different solar times. Project outcomes involve applying heat transfer loss theory via conduction across individual receiver layers, conducting experiments to assess coating efficiency and receiver performance. The team successfully assembled the system with four parallel mirror rows, spaced at 1.5 feet intervals to minimize shadow casting. The solar receiver features two glass tubes, air gaps held by 3D-printed end caps, and an internal mesh turbulator to enhance heat transfer through flow turbulence. The ultimate objective was to heat water sufficiently for membrane distillation (around 40°-70°C). Experimental testing on a windy day with clouds resulted in a final water temperature of 38°C after 3 hours. Receiver efficiency, calculated by comparing solar energy incident on the pipe to energy transferred to water, was 17.5%. While not within the desired range, these promising results, considering surrounding conditions, deem the project successful in creating an efficient heating system for membrane distillation. Recommendations and improvements are possible, confirming the project as a successful proof of concept.

Techno-economic comparison of fixed and tracking flat plate solar collectors in the northern hemisphere

Thermal energy for water and space heating can be trapped using flat plate solar collectors (FPSC). Several techniques, such as using a polymer as the collector material, nanofluid as the heat transfer fluid, and phase change material (PCM), have been proposed to enhance the thermal performance of the FPSC. The present paper concentrates on utilizing solar trackers (dual and single axis) as an enhancement device to improve the performance of the FPSC. For the single-axis trackers, various tracking orientations such as East-West (EW), North-South (NS), Inclined East-West (IEW), and Vertical-axis (V) are taken into consideration. The considered locations are in the latitude range from 20 to 70°N, hence spread across the African, Asian, European, and North American continents. Unlike prior literature, the more accurate Perez diffuse model with the hourly weather data are utilized in this study. The system performance is assessed and ranked in terms of useful energy from the collector and economic indicators, unlike the previous studies with no economic feasibility analysis as the key practical point for decision making. The study aims to provide a comprehensive outlook for engineers, designers, installers, and policymakers in the adoption of FPSC incorporated with various dual and single-axis trackers in the northern hemisphere.

INVESTIGATING THE FACTORS IMPACTING THE ADOPTION OF SOLAR WATER HEATERS AMONG THE RESIDENTS OF COOPERATIVE HOUSING SOCIETIES- STUDY CONDUCTED IN CITIES OF INDIA

According to U. S. Energy Department, water heating accounts for about 18% to 25% of household energy consumption. World today faces energy security problems due to its demand and supply disruptions. Using solar energy for water heating becomes a good option. Solar energy is renewable, clean and green thus its usage helps in sustainable development. This research paper tries to identify the factors impacting the adoption of solar water heaters among the residents of Cooperative Housing Societies (CHSs) in six cities of India these factors will help the manufacturers/suppliers of solar water heaters to frame marketing strategies for adoption and augmenting the sales of these products.