Water Heating

This publication introduces calculations of circulation pump power for solar water heater, forced circulation system. The theoretical power is estimated as 0.5 Watt, while the nominal power of the relevant pump is 6 Watt. Energy consumption of such pump is 25 kWh/year. The required water flow is 2 liters/minute and the pump's head is 1.5 meter.

The paper reviews the available journalism associated with solar heating and solar tracking. Sun being the never-ending source of energy, has motivated and developed many technologies as solar heating, thermal energy, electricity generation etc. The main aim of each study is to enhance the heating efficiency. Most of the techniques used for solar heating included solar tracking, collectors, phase change materials, active systems, spiral tube for increasing efficiency of solar water heating process. This paper aims to explore similar systems of this type. I. INTRODUCTION Solar energy systems have emerged as a viable source of renewable energy over the past two or three decades, and are currently used on large scale in commercial as well as domestic applications. Several literature studies are based on the utilization of solar collectors to implement such applications as light, window covering systems, cookers and heaters. Water heaters have been becoming common now a days in the countries for almost every day use. The conventional heaters such as geysers and boilers are environmentally harmful because the heating process requires fossil fuel burning and greenhouse gas emissions. The higher energy usage for heating purpose is not only creating pressure on national grid for excess supply of electricity but also affecting electricity price badly. One of the alternative technologies is solar water heating, which can be used for heating water without harming the environment by simply using solar power. Also, a modified version of it can be used i.e., solar tracking water heater to increase its efficiency and availability of heated water for more time of the day. In general terms, the power developed in such applications depends primarily upon the quantity of solar energy or solar power captured by the collector, and therefore the matter of developing tracking schemes that are capable of following the trajectory of the sun throughout the day over the years is also important. Current review illustrates various research on the various models and systems related to Solar heating and solar tracking.

This work introduces development of formulas of heat transfer in solar water heater pipes to allow calculations of energy losses in pipes.
Solar legislation in Israel requires installation of solar water heaters in new buildings up to 9 floors from roof. The legislation from year 1980 is based on technology of late 70's. This publication compares old types of installation (steel pipe) with the current common practice (2017) of installation of solar water heaters in Israel.
Publication of "Energy Balance of Solar Water Heaters: Thermosyphonic Systems" [8] created new tool which allowed to make this work.
This work analyzes a possibility of installation of thermosyphonic systems in lower floors than 4th floor under the roof.
The results are energy losses, waste of time waiting for hot water and waste of water depending on pipe's length and distance to apartment.
This publication may be helpful for techno-economic evaluation of water heating options and determination of the optimum solutions. It also contains large volume of useful formulas, data and information and can serve as basic material for solar water heaters calculations.

Este estudo foi realizado para avaliar a viabilidade dos sistemas de aquecimento de água mais utilizados no município de São Paulo: o elétrico, a gás e o solar,
apresentados nas formas de passagem ou por acumulação. Através da aplicação desses sistemas à planta de uma residência situada no mesmo município, o autor
analisa as necessidades de adaptação à estrutura física dos projetos e as particularidades de cada sistema, como os custos de aquisição, custos de mão-de-obra especializada, custos com infraestrutura e custos com a utilização mensal do equipamento ao longo de um período. Com base nos dados levantados, o autor
apresenta os resultados de uma análise comparativa entre todos os sistemas, explicitando as suas vantagens e, através de uma comparação entre os sistemas,
determina qual dentre eles é o mais viável economicamente.

This work have a proposal to analyze the heating systems most used in the São Paulo city: electrical, gas and solar, in a two different types: passage or accumulate. This study of installation systems in a domestic plant situated in the same place, will be analyzed the necessities of structural adaptations and indirect rates, as the price of purchase, specialized installation and monthly costs with equipment after uses in a long time. At the end, will be showed the results of analysis between the heating systems, advantages to all systems and what have the less expense.

Uninsulated pipes of solar waters heaters in Israel increase national electricity consumption by 200 millions kWh/year, 40 millions USD per year. Simple solution having 2-4 months return of investment period can stop this waste. This work introduces energy balance of thermosyphonic solar water heater (SWH) without pipes' thermal insulation. The results are used for economic evaluation.

In the present work, a survey of the various types of solar thermal collectors and applications is presented. Solar thermal collector is a device that absorbs the incoming solar radiation, converting it into heat at the absorbing surface, and transfers this heat to a fluid flowing through the collector.

The objective of this work is to evaluate the technical and economic feasibility of integrating a Fresnel and a flat plate collectors solar fields to generate saturated steam and hot water, respectively, for a poultry slaughterhouse located in the west of Parana state – Brazil. The process heat is supplied by a conventional biomass steam generator, with a nominal capacity of 40 t/h of saturated steam at 1000 kPa (abs). The Fresnel solar field was proposed to operate in parallel with the boiler to generate 50 % of its nominal load at design point condition. In this regard, the Fresnel solar field aperture area was designed as 24,244 m² based on LF-11 primary mirrors, representing an investment of EUR 6.34 million. In an annual basis, the biomass economy reached 7157 t after simulations for a typical meteorological year – reducing the capital expenditures related to biomass purchasing by EUR 3.5 thousand per year. Regarding the flat plate collectors solar field, it was designed to supply 100 m³/h of hot water at 50°C at design point – i.e., the total process hot water consumption. In this regard, the solar field area was calculated as 3132 m², leading to an investment of EUR 414.9 thousand. In an annual basis, the biomass economy reached 1486 t after simulation of a typical meteorological year – reducing the capital expenditures related to biomass purchasing by EUR 63.4 thousand per year. Both integration layouts were here analysed in terms of economic feasibility and sensitive analyses were performed by changing the solar multiple and costs of Fresnel and flat plate collectors systems.

Ülkemizdeki yüzme havuzlarının kullanım dönemleri dikkate alındığında, ilkbahar ve sonbahar aylarında ısıtma ihtiyacı oluşmakta, yazın ise ısıtmaya ihtiyaç duyulmamaktadır. Ancak sıcak iklim bölgelerinde yaz aylarında dış ortam sıcaklığı istenilen havuz suyu sıcaklığından çok daha yüksek olduğundan soğutmaya da ihtiyaç duyulmaktadır. Havuz suyunun soğutulması ile sıcak iklim bölgelerindeki açık yüzme havuzları tüm yıl boyunca kullanılabilecektir. Bu çalışmada sıcak iklim bölgelerindeki havuz suyunu istenilen sıcaklığa soğutmak için kullanılan ısı pompalarının farklı çalışma şartlarındaki performansları incelenmiştir. Belirli ölçüdeki bir havuzun istenilen su sıcaklığına getirilmesi için gerekli soğutma kapasitesi farklı iklim koşulları için belirlenmiş ve karşılaştırılmıştır. Isı pompaları hava kaynaklı olarak seçilmiştir. Çalışmada her iklim bölgesi için ısı pompalarının çalışma süresi ve soğutma ihtiyacı belirlenmiştir. Yapılan analizde soğutulacak havuz için seçilen ısı pompasının performansının doğrudan hava koşullarına bağlı olarak değiştiği görülmüştür. Hava sıcaklığının artması ile ısı pompasının EER değeri azalmaktadır.

Although the Peltier sub-cooled trans-critical CO2 cycle concept has been applied for refrigeration, which typically involves discharging the heat into ambient air, this system is rarely considered for heat pumping purposes. Therefore, this research aims to expand the scope of the Peltier sub-cooled trans-critical CO2 cycle into heat pump water heating where the generated heat is uniquely discharged into water at temperatures progressively higher than ambient. The heat flows between the CO2 and flowing water are modelled as Nusselt based convective heat transfers where a 1D model is imposed to the direct gas cooler to improve simulation accuracy. Moreover, important but often neglected characteristics such as Peltier device size and Peltier heating factor (PHF) will also be analyzed. Results indicate that the PHF has an extremely strong influence on the overall system’s coefficient of performance (COP). Specifically, an optimal PHF value exists as a trade-off between the benefit of sub-cooling and the losses due to reduced CO2 mass flow rate, the latter of which caused reductions in the convective heat transfer coefficient and the direct gas cooler’s heating capacity. In the meantime, although larger Peltier device sizes improves the system COP, the improvement will converge towards a specific maximum.

This research was aimed to observe the performance of water heating as an air moisture controller device in a hospital surgery room. The way the research was outside air in 27 degrees until 30 degrees celcius and moisture of 60 until 70 percent made suitable with requirement conditions determined for surgery room in the hospital i.e. 19 until 24 degrees celcius and moisture of 45 until 60 percent. To make that condition, the surgery room was equipped with air conditioner machine and water heating as an air moisture controller device. Hot water was circulated in water heating and air moisture was measured by a hygrometer. Out of this research it obtained: measuring moisture value higher than theoretic moisture value. Calorie volume in water heating increased with water volume that was constant so that water heating could control air moisture. There was a suitability in an air moisture ratio and calorie volume in water heating so that air moisture in surgery room could be measured as requirements.

Tujuan penelitian ini adalah mengamati kinerja water heating sebagai alat pengendali kelembaban udara di dalam ruang operasi rumah sakit. Cara penelitian yaitu udara luar pada suhu 27 sampai dengan 30 derajat celcius dan kandungan kelembaban 60 sampai 70 persen dibuat sesuai dengan kondisi persyaratan yang ditentukan untuk ruang operasi di rumah sakit yaitu suhu 19 sampai 24 derajat celcius dan kelembabannya 45 sampai dengan 60 persen. Untuk membuat kondisi tersebut ruang operasi dilengkapi mesin pengkondisian udara dan water heating sebagai alat pengendali kelembaban udara. Air panas disirkulasikan pada water heating dan kelembaban udara diukur dengan hygrometer. Dari penelitian ini didapatkan antara lain: nilai kelembaban pengukuran lebih tinggi dari nilai kelembaban teoritis. Jumlah kalor pada water heating meningkat dengan volume air yang konstan maka water heating dapat mengendalikan kelembaban udara. Rasio kelembaban udara ada kesesuaian dengan jumlah kalor pada water heating sehingga kelembaban udara di ruang operasi dapat diatur sesuai persyaratan.

Phosphorus removal was estimated for two biotopes in the heating zone of Bereza HPP (Brest region, Belarus) The flow of phosphorus was linearly associated with benthos biomass and varied from 13,2 (in the hot channel) to 68,0 (in the cooling pond) mgP/m2*d, and 77-100% of the flow of phosphorus  was in phosphate form. It was revealed that biotic processes were the main mechanism of phosphorus removal from the bottom sediments to water in the pond, while in was molecular diffusion in the hot channel.
The dominant mesobenthic species Stenocypris major (Ostracoda), which was an invasive alian species in Bereza HPP cooling system, provided from 5% (in the channel) to 30% (in the pond) of the biotic flow of phosphorus from the bottom sediments into the water.

Due to the increase of electricity prices in South Africa and the World, there exists the need for energy efficient water heating systems. The authors of this paper conducted a literature study on existing water heating systems. The study shows that there is a possibility of designing more efficient water heating system at lower cost. An in-line water heating system for industrial applications was designed and tested. Before the system was designed a Finite Element Method
analysis of the system was carried out to predict the systems’ pressure and temperature. During a physical model test the energy consumption was measured and compared to a conventional storage water heating system. The designed in-line water heating system is shown to be more energy efficient than the conventional storage water heating system. It also had a variety of advantages such as: size, adaptability to a variety of locations, and robustness.

Although the Peltier sub-cooled trans-critical CO2 cycle concept has been applied for refrigeration, which typically involves discharging the heat into ambient air, this system is rarely considered for heat pumping purposes. Therefore, this research aims to expand the scope of the Peltier sub-cooled trans-critical CO2 cycle into heat pump water heating where the generated heat is uniquely discharged into water at temperatures progressively higher than ambient. The heat flows between the CO2 and flowing water are modelled as Nusselt based convective heat transfers where a 1D model is imposed to the direct gas cooler to improve simulation accuracy. Moreover, important but often neglected characteristics such as Peltier device size and Peltier heating factor (PHF) will also be analyzed. Results indicate that the PHF has an extremely strong influence on the overall system’s coefficient of performance (COP). Specifically, an optimal PHF value exists as a trade-off between the benefit of sub-cooling and the losses due to reduced CO2 mass flow rate, the latter of which caused reductions in the convective heat transfer coefficient and the direct gas cooler’s heating capacity. In the meantime, although larger Peltier device sizes improves the system COP, the improvement will converge towards a specific maximum.

https://doi.org/10.1016/j.enconman.2019.01.104

In this paper, the authors provide the design, heat flow analysis and pressure analysis of a commercial energy efficient in-line water heating system in South Africa. The designed commercial in-line water heating system captures the energy consumption, flow rate, temperature and pressure during operation and accordingly responds on these values to increase the energy efficiency of the system. The user is constantly aware of the energy consumption and cost during operation and can choose to switch to a more economical setting to conserve energy. A central processor with PID control was used to optimize the energy consumption of the in-line water heating system. An overview on the design and results of the heat flow analysis and pressure analysis are provided.