Intermediate Energy Technology in China

China, the largest and most populous of all the developing countries, has been concentrating on developments in coal mining, hydroelectric generation, and biogass production and now the latest addition is the use of solar energy. Providing fuel and electricity for development of diverse local light industries, for agricultural modernization and for household consumption, these projects while small are introducing modern technology in a way that allows for large-scale labor participation and reduces capital investment to the essential minimum. The part of the energy output for private consumption helps to raise the standard of living in China and to ease household work; many peasants acquire various basic technical skills, which are necessary for more sophisticated work to be done in the future; local production of a substitute fuel and electricity, previously produced by large enterprises, brings not only considerable savings but also greatly reduces the need for energy-intensive transportation and transmission of primary energy. Environmental implications of small energy projects are mostly positive: the availability of coal, electricity and biogas reduces or even eliminates the need for using firewood, grasses or crop residues as fuel, which means they can be used for composting or as fodder or conserved. The role ofmore » the small dams for irrigation and flood control might be, in many instances, economically more important than power generation. The same may be true about improvement of hygienic conditions and concomitant reduction of infections and parasitic diseases due to biogas generation. Biogas fermentation also yields an excellent fertilizer, representing further savings. While effective large-scale utilization of solar radiation faces difficult obstacles, simple solar furnaces are economically viable and can be used intermittently for household cooking, space and water heating, cooling, water desalination and crop drying. 21 notes. (MCW)« less

There are two main types of solar power systems: thermal and photovoltaic (PV). The direct thermal use of solar energy for water heating is very old, mature and cheap technology. The world capacity of such solar thermal energy is over 400 GW‐thermal and is expected to increase sharply. For electricity generation, concentrated solar power is a promising technology for places with the right environmental conditions for generating electricity with higher efficiency than PV technology. This technology is only practical for high electrical power generation and storage, because of the complicated technology with relatively high initial and running costs. The use of solar energy is very attractive in many applications such as water heating, solar cooling (heat‐powered air conditioning), and even water desalination. Solar thermal technologies have various levels of temperature and pressure, with various heat‐conducting and storage materials.

Solar Domestic Water Heating is a comprehensive introduction to all aspects of solar domestic water heating systems. As fossil fuel prices continue to rise and awareness of climate change grows, interest in domestic solar water heating is expanding. Solar water heating technology is the most environmentally-friendly way to heat water. This fully-illustrated and easy-to-follow guide shows how domestic solar water heating systems work, the different types of systems, types of collectors, both flat plate and evacuated tube, types of storage tanks and other accessories. It also shows how systems are installed and explains how solar water heating can be integrated into existing water heating systems. Numerous examples from around the world have been included. The ideal guide for plumbers, heating engineers, builders and architects, housing and property developers, home owners and DIY enthusiasts, and anyone who needs a clear introduction to solar water heating technology.

This article reviews the application of solar energy technology in Cyprus and presents an energy analysis, including the use of solar energy, in the island. Cyprus has no conventional sources of energy and is dependent on imported oil. However, its geographical position is such that it is one of the countries where the potential for solar energy utilisation is very high. Cyprus began manufacturing solar water heaters in the early 1960s and today it produces more than 30 000 m2 of solar collectors yearly. It is estimated that more than 130 000 solar water heaters are in operation, which provide the equivalent of 9% of the total electricity consumption in the island, and corresponds, approximately, to 4% of the national energy consumption. However, the use of solar energy for space heating and cooling provides a further challenge because it does not appear to be economic under the climatic conditions and system design practices currently prevailing in Cyprus. The article provides a statistical analysis of the energy demand and identifies areas of further growth for solar energy technology.

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.

The study focused on the operational performance of an installed hybrid solar assisted air source heat pump (ASHP) water heater on a residence. The hybrid solar assisted ASHP water heater comprised of a 200 L solar water heater (SWH) that preheat the water and a 150 L, 1.2 kW ASHP water heater that heat the water to 55 oC. Temperature sensors, flow and power meters are installed at specific locations on the hybrid solar assisted ASHP water heater. These sensors measured the water and refrigerant temperatures, volume of hot water heated by the ASHP unit and the volume of hot water consumed by the occupants as well as the electrical power consumed by the ASHP unit. The preliminary results depict that in the month of February 2019, the average weekday volume of water consumed by the occupants was 238.75 L while the electrical energy consumed, the thermal energy gained and the coefficient of performance (COP) of the ASHP water heater was 1.73 kWh, 6.02 kWh and 3.43, respectively. The average weekday solar energy harnessed, the thermal energy gained by SWH and the solar fraction achieved by the SWH was 11.91 kWh, 6.17 kWh and 0.52, respectively. It can be concluded that, by implementing the hybrid solar assisted ASHP water heater for hot water heating, the overall performance was better compared to the conventional technology.

In search for sustainable globally cost-effective energy efficient building solar system – Heat recovery assisted building integrated PV powered heat pump for air-conditioning, water heating and water saving

Wind-mills were widely used for grinding corn in the last century in Hungary. The use of solar energy for water heating, taking a bath, shower, and drying crops has had a tradition for a long time. This article presents in what proportion the two types of energy are disposable in the course of the year, how this difference between the simultaneous disposability of the two types of sources of energy changes depending on seasons, and by what a diffusion and variance in a month, a part of a day, or an hour the examined parameters can be characterized.

The aim of this paper is to assess solar potential and investigate the possibility of using solar water heating for residential application in Inland Norway. Solar potential based on observation and satellite-derived data for four typical populous locations has been assessed and used to estimate energy yield using two types of solar collectors for a technoeconomic performance comparison. Based on the results, solar energy use for water heating is competitive and viable even in low solar potential areas. In this study it was shown that a typical tubular collector in Inland Norway could supply 62% of annual water heating energy demand for a single residential household, while glazed flat plates of the same size were able to supply 48%. For a given energy demand in Inland Norway, tubular collectors are preferred to flat plate collectors for performance and cost reasons. This was shown by break-even capital cost for a series of collector specifications. Deployment of solar water heating in all detached dwellings in Inland could have the potential to save 182 GWh of electrical energy, equivalent to a reduction of 15,690 tonnes of oil energy and 48.6 ktCO2emissions, and contributes greatly to Norway 67.5% renewable share target by 2020.

Exploitation of solar energy in Cyprus

Domestic water heater corresponds to 25% of the house energy consumption and can play an important role to reduce energy house expenses. Solar energy offers a preferred renewable energy resource because of its economic and environmental advantages. It is considered the best alternative to reduce domestic water heater energy consumption cost. Converting solar energy into heat can be considered among the simplest used systems. Solar thermal conversion is more efficient than solar electrical direct conversion method. Solar water heater systems are particularly easy to use and to repair. The integrated conical solar collector water heater (ICSCWH) is so far the easiest among water heating systems. The ICSCWH converts directly and efficiently the solar flux into heat. In order to expand the utilization of ICSCWH systems, many design modifications have been examined and analyzed. This study provides an experimental investigation and mathematical simulation of an ICSCWH system equipped with a glass cover resulting in the increase of the maximum absorption. Integrating the cone-shaped heat collector with an aluminum spiral pipe flow system may enhance the efficiency of the proposed system. In order to maximize the solar radiation of the system, the solar water heater has been designed in a conical shape, which removes the need to change its orientation toward the sun to receive the maximum sun radiation during the day. In this system, the heating of water has been obtained using the spiral pipe flow without the use of the solar cells and mirrors in order to reduce the total cost. The storage water tank of this system is coupled with a conical solar collector. Based on the above design, the solar water heater has been fabricated and tested. In addition, an analytical modeling approach aiming to predict the flow rate within the conical integrated collector storage solar water heater (ICSSWH) and its efficiency, was developed. Modeling through a numerical simulation approach based on energy equations was performed. Considering the entire water amount and the total area of the cone, the amount of water (facing the sun per unit absorbing area in the two symmetrical parts of the system) is found to increase, which is expected to reach a maximum water temperature at a high performance. Our experimental findings show that the daily performance is around 32% and the highest water temperature of about 45°C is obtained in the system at 4 pm, according to seasons and weather conditions. An efficient and simple mathematical simulation approach for the new conical solar water heater is described then validates using experimental data.

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

Mediterranean European cities are characterized by high population density and limited space for large-scale implementation of renewable energy installations. This paper addresses the optimization of renewable energy installations in Mediterranean dwellings with the scope of increasing their energy contribution and cost-effectiveness. In a case study for Malta, the three technologies studied were solar photovoltaics, solar water heating, and heat pump water heating. Technical and economic analyses were performed on a number of reference configurations using Polysun software (version 2022.8). Sensitivity analyses were also conducted to study the impact that different technical and economic factors have on the performance of the configurations considered. Finally, comparisons were made between the techno-economic results obtained from the reference and sensitivity analyses. Based on data collected, the presence of renewable energy source (RES) technologies in the residential sector of Malta was characterized and correlated with the types of dwellings considered. Among the results obtained, it was found that although a solar RES installation may experience some shading, this does not mean that it is rendered economically unfeasible. Moreover, from the simulations conducted, electrical energy storage technology was considered as too premature unless strongly subsidized, making economic sense only in specific circumstances. On the other hand, although heat pump water heating technology is also relatively modern, it was concluded to be the most beneficial in terms of both energy yield and economic benefit, generally speaking. Furthermore, it was determined that in a higher occupancy dwelling, solar water heating (SWH) and heat pump water heating (HPWH) result in considerably more attractive energy savings.

Chapter 5 - Solar Water and Space-Heating Systems

In terms of environmental sustainability, the barriers—and interactions between these barriers—to the use of solar energy for active and passive heating in residential buildings stem from location-specific housing production patterns and the actors involved in these patterns. A clear definition of hierarchies and priorities between barriers helps managers set strategic priorities and action plans to find solutions. After the earthquake in Van in 2011, 6000 hectares of land were opened for new development, and research using the sampling method discovered that the most common type of housing production in the city is the build-to-sell housing production method. The actors involved in build-to-sell housing production are technical staff, local–central administrations, entrepreneurs, end users, landowners, financial companies, non-governmental organizations, and building inspection institutions. This article examines the barriers to the use of solar energy for active and passive heating purposes, the interactions between these barriers using ISM and MICMAC methods, and the build-to-sell housing production method and actors. Barriers were identified through a literature review and semi-structured interviews. The barriers were further categorized under eight main headings according to their subject matter. The hierarchies of barriers in creating problems and solutions were determined using ISM and MICMAC methods and the findings were interpreted. In the City of Van, with regard to the houses produced via the build-to-sell production method, the barriers against the use of solar energy for heating purposes in houses considering active and passive methods are ranked in order of priority in creating the problem and the solution. Barriers caused by political and administrative issues are ranked first; barriers caused by social awareness and end users are ranked second; barriers caused by social and sociological events are ranked third; barriers caused by laws and regulations are ranked fourth; barriers caused by the knowledge, skills, and awareness of designers are ranked fifth; barriers caused by deficiencies in technical issues are ranked sixth; and barriers caused by economic and financial issues are ranked seventh. Even though the barrier caused by the working mode of build-to-sell productions is the largest in creating the problem, it is the least effective barrier to solving the problem in the ISM hierarchical and MICMAC schemes. The research process is presented in the Methods section.