Simulation of Thermal Performance of Solar Collector Arrays

1981 ◽  
Vol 103 (3) ◽  
pp. 258-267 ◽  
Author(s):  
A. H. Fanney ◽  
W. C. Thomas
Keyword(s):  
Heat Source ◽  
Water System ◽  
Flow Characteristics ◽  
Longwave Radiation ◽  
Heat Losses ◽  
Hot Water ◽  
Outdoor Environment ◽  
Energy Output ◽  
In Series ◽  
Electric Heat

An experimental method is described for simulating the useful energy supplied by collector arrays during tests of solar water heating systems. The method uses an electric heat source to simulate the absorbed solar energy in series with nonirradiated collectors to simulate the concurrent heat losses. This configuration maintains the collector-loop flow characteristics which are important for system tests. Expressions are developed for programming the heat source for collector arrays connected in parallel and series combinations with the heat source located either upstream or downstream from the nonirradiated array. Thermal modeling of representative arrays is used to investigate the consequences of using linearized collector efficiency curves to program the heat source and of using nonirradiated collectors to simulate heat losses. The absence of absorbed solar radiation in collector covers indoors is shown to partially cancel the effects of generally higher windspeed and increased longwave radiation loss in the outdoor environment. In typical situations, the analytical model showed that the use of nonirradiated collectors in series with an electric heat source may give up to 10 percent higher useful energy output as compared to an irradiated array. The difference, however, can be reduced by closely matching indoor and outdoor environmental conditions and by locating the heat source downstream from the nonirradiated collector array. The results of experiments to verify the performance of a nonirradiated array with a downstream electric heat source are presented. Day-long tests of a domestic solar hot water system with irradiated collectors were repeated using a nonirradiated array with a downstream heat source. The measured useful energy in the two cases was consistent with the results of the analytical investigation.

Analysis on the Technical Solutions of the Heat Source of the Geothermal Heat Pump System

2014 ◽  
Vol 953-954 ◽  
pp. 650-654
Author(s):  
Chao Yi Tan ◽  
Hui Zhu ◽  
Hai Hua Hu ◽  
Meng Meng Wang ◽  
Han Qing Wang
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Heat Load ◽  
Hot Water ◽  
Geothermal Heat ◽  
Pump System ◽  
Heat Pump System ◽  
Geothermal Heat Pump ◽  
In Series ◽  
Technical Solutions

Taking the geothermal heat pump system in the campus of Hunan University of Technology for example, three technical solutions of the heat source of the system were analyzed in terms of the condensing heat load, the annual unbalanced heat load and the energy efficiency ratio (EER) of the system. In addition, comparison was conducted among the solutions. The results indicate that the solution 3, which has a cold and hot water integrative unit and hot water unit connected in series, meanwhile has a cooling tower for auxiliary cooling, shows better performance among all the solutions. The analysis on the solution of heat source of geothermal heat pump system, which usually contains the analysis on the condensing heat load, annual unbalanced heat load and EER, is of great significance for the design and development of the geothermal heat pump system with lower coat and higher EER.

Effect of connection mode and mass flux on the energy output of a PVT hot water system

Solar Energy ◽  
2017 ◽  
Vol 158 ◽  
pp. 285-294 ◽  
Author(s):  
Yanping Yuan ◽  
Liping Ouyang ◽  
Liangliang Sun ◽  
Xiaoling Cao ◽  
Bo Xiang ◽  
...  
Keyword(s):  
Mass Flux ◽  
Water System ◽  
Hot Water ◽  
Energy Output

The Optimal Peak-Adjusting Parameters of Low-Temperature Heat Source Heating

Solar Energy ◽  
2005 ◽  
Author(s):  
Ronghua Wu ◽  
Chenghu Zhang ◽  
Dexing Sun
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Water System ◽  
Weather Conditions ◽  
Integrated System ◽  
Hot Water ◽  
Cold Weather ◽  
Design Parameters ◽  
Temperature Heat

The integrated low and high temperature heating water system consists of heat pump heat source and boiler heat source. The heat pump heat source abstract heat from low temperature heat source and produce hot water up to 65°C. During mild weather, the 65°C hot water is sufficient for building heating. During cold weather conditions, the boiler heat source will have to be used to produce hot water at 90°C or higher to satisfy the building comfort. To improve the system economy, the integrated system has to maximize the use of the low temperature heat source since it is free. This paper presents a theoretical models and analysis to optimize the system design parameters.

scholarly journals Hybrid Domestic Hot Water System Performance in Industrial Hall

Resources ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 65 ◽  
Author(s):  
Edyta Dudkiewicz ◽  
Natalia Fidorów-Kaprawy
Keyword(s):  
Heat Source ◽  
Water Consumption ◽  
Waste Heat ◽  
Variable Temperature ◽  
Water System ◽  
Analysis Data ◽  
Economic Benefits ◽  
Hot Water ◽  
Domestic Hot Water ◽  
Alternative Sources

The renewable and waste heat sources implemented for the preparation of domestic hot water (DHW) allow for energy conservation and environment protection along with resource savings and economic benefits. The solutions, including non-conventional sources, are especially demanded in large halls in which energy and water consumption are crucial for maintenance costs. In this article, energy analysis of a DHW preparation system for workers’ hygienic purposes in a industrial hall was performed. The DHW preparation system consisted of three sources: a flue gases heat exchanger as the waste heat source, solar collectors as the renewable heat source and a gas boiler as the conventional source. In the analysis, data of a variable-temperature supply of water and hourly water consumption data from the measurements in the industrial hall, located in Poland, were applied. The results for all of the 8760 h of one year were examined. The analysis outcomes show that implementation of non-conventional sources can supply 81.4% of energy needed for DHW preparation, avoiding a lot of running costs; just 18.6% of heat demand had to be obtained from a gas boiler. The analysis also confirms that the system may operate correctly when the appropriate device size is applied, along with a proper control strategy that avoids overheating water and uses alternative sources.

Three Experimental Techniques to Duplicate the Net Thermal Output of an Irradiated Collector Array

1983 ◽  
Vol 105 (1) ◽  
pp. 92-100 ◽  
Author(s):  
A. H. Fanney ◽  
W. C. Thomas
Keyword(s):  
Heat Source ◽  
Solar Collector ◽  
Water Systems ◽  
Hot Water ◽  
Test Method ◽  
Outdoor Environment ◽  
Experimental Techniques ◽  
Laboratory System ◽  
Domestic Hot Water ◽  
Thermal Output

A relevant and repeatable test method is required to provide a means for rating solar domestic hot water systems. The test method should be independent of the geographical location of the laboratory and the prevailing outdoor environment. Three experimental techniques which reproduce the net thermal output of a normally irradiated solar collector without the use of a solar simulator are investigated. These techniques include the use of an in-line electrical heat source only, use of a nonirradiated collector array in series with a heat source, and the use of electrical strip heaters attached to the back of nonirradiated absorber plates. Two single-tank direct solar domestic hot water systems have been fabricated at the National Bureau of Standards to validate each experimental technique. The solar collector array of one system is subjected to outdoor meteorological conditions. The second system, used to validate the experimental techniques, is located entirely indoors. Daily tests of the solar domestic hot water system with the irradiated collector array were subsequently repeated for the laboratory system using the three experimental techniques. Based on results from several nearly clear and intermittently cloudy days, all three simulation techniques reproduce the net thermal output of the normally irradiated collector array within 4 percent. Pump controller operation can be closely reproduced using two of the techniques. Advantages and limitations of each method are discussed.

Experimental study on a novel PV/T air dual-heat-source composite heat pump hot water system

2015 ◽  
Vol 108 ◽  
pp. 175-184 ◽  
Author(s):  
Gang Wang ◽  
Zhenhua Quan ◽  
Yaohua Zhao ◽  
Chenming Sun ◽  
Yuechao Deng ◽  
...  
Keyword(s):  
Experimental Study ◽  
Heat Source ◽  
Heat Pump ◽  
Water System ◽  
Hot Water ◽  
Composite Heat

DETERMINING THE PROFITABILITY OF GREENHOUSE ELECTROTECHNOLOGIES: A MODELING APPROACH

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 249a-249
Author(s):  
Eric A. Lavoie ◽  
Damien de Halleux ◽  
André Gosselin ◽  
Jean-Claude Dufour
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Water System ◽  
Heat Pumps ◽  
Hot Water ◽  
Pump System ◽  
Heat Pump System ◽  
Artificial Lighting ◽  
Hot Air ◽  
Marketable Fruit

The main objective of this research was to produce a simulated model that permitted the evaluation of operating costs of commercial greenhouse tomato growers with respect to heating methods (hot air, hot water, radiant and heat pumps) and the use of artificial lighting for 1991 and 1992. This research showed that the main factors that negatively influence profitability were energy consumption during cold periods and the price of tomatoes during the summer season. The conventional hot water system consumed less energy than the heat pump system and produced marketable fruit yields similar to those from the heat pump system. The hot water system was generally more profitable in regards to energy consumption and productivity. Moreover, investment costs were less; therefore, this system gives best overall financial savings. As for radiant and hot air systems, their overall financial status falls between that of the hot water system and the heat pump. The radiant system proved to be more energy efficient that the hot air system, but the latter produced a higher marketable fruit yield over the 2-year study.

DYNAMICS OF THERMAL LOSSES BY CONVECTION AND RADIATION OF THE SPHERICAL HEAT ACCUMULATOR OF SOLAR PLANTS

2020 ◽  
Vol 4 (41) ◽  
pp. 57-62
Author(s):  
SHAVKAT KLYCHEV ◽  
◽  
BAKHRAMOV SAGDULLA ◽  
VALERIY KHARCHENKO ◽  
VLADIMIR PANCHENKO ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Heat Loss ◽  
Initial Conditions ◽  
Water System ◽  
Heat Losses ◽  
Research Purpose ◽  
Heat Accumulator ◽  
Water Heaters ◽  
Intrinsic Radiation ◽  
Over Time

There are needed energy (heat) accumulators to increase the efficiency of solar installations, including solar collectors (water heaters, air heaters, dryers). One of the tasks of designing heat accumulators is to ensure its minimal heat loss. The article considers the problem of determining the distribution of temperatures and heat losses by convection and radiation of the heat insulation-accumulating body (water) system for a ball heat accumulator under symmetric boundary conditions. The problem is solved numerically according to the program developed on the basis of the proposed «gap method». (Research purpose) The research purpose is in determining heat losses by convection and radiation of a two-layer ball heat accumulator with symmetric boundary conditions. (Materials and methods) Authors used the Fourier heat equation for spherical bodies. The article presents the determined boundary and initial conditions for bodies and their surfaces. (Results and discussion) The thickness of the insulation and the volume of the heat accumulator affect the dynamics and values of heat loss. The effect of increasing the thickness of the thermal insulation decreases with increasing its thickness, starting with a certain volume of the heat accumulator or with R > 0.3 meters, the heat losses change almost linearly over time. The dynamics of heat loss decreases with increasing shelf life, but the losses remain large. (Conclusions) Authors have developed a method and program for numerical calculation of heat loss and temperature over time in a spherical two-layer heat accumulator with symmetric boundary conditions, taking into account both falling and intrinsic radiation. The proposed method allows to unify the boundary conditions between contacting bodies.

scholarly journals New Deterministic Mathematical Model for Estimating the Useful Energy Output of a Medium-Sized Solar Domestic Hot Water System

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2753
Author(s):  
Miroslaw Zukowski ◽  
Walery Jezierski
Keyword(s):  
Thermal Power ◽  
Optimization Procedure ◽  
Climatic Conditions ◽  
Point Of View ◽  
Hot Water ◽  
Energy Output ◽  
Daily Consumption ◽  
Software Environment ◽  
Optical Efficiency ◽  
Domestic Hot Water

According to the authors of this paper, the mathematical point of view allows us to see what sometimes cannot be seen from the designer’s point of view. The aim of this study was to estimate the influence of the most important parameters (volume of heat storage tanks, daily consumption of domestic hot water, optical efficiency, heat loss coefficient, and total area of a solar collector) on the thermal power output of solar domestic hot water (SDHW) system in European climatic conditions. Three deterministic mathematical models of these relationships for Madrid, Budapest, and Helsinki were created. The database for the development of these models was carried out using computer simulations made in the TRNSYS software environment. The SDHW system located at the Bialystok University of Technology (Poland) was the source of the measurement results used to validate the simulation model. The mathematical optimization procedure showed that the maximum annual useful energy output that can be obtained from 1 m2 of gross collector area is 1303 kWh in the case of Madrid, 918.5 kWh for Budapest, and 768 kWh for Helsinki weather conditions.

Role of Dissipation Characteristics in Predicting Flow from Dissimilar Centrifugal Pumps

1994 ◽  
Vol 208 (4) ◽  
pp. 285-294 ◽  
Author(s):  
E A Bunt ◽  
B Parsons ◽  
F Holtzhausen
Keyword(s):  
Flow Characteristics ◽  
Maximum Flow ◽  
Centrifugal Pumps ◽  
Graphical Solution ◽  
Dissipative Flow ◽  
In Series ◽  
Lower Maximum ◽  
Output Field ◽  
High Series

Examination of flows in a particular case of dissimilar pumps coupled in series or in parallel (without check valves) showed that the ‘classical’ graphical solution of combined characteristics in the [+H, +Q] quadrant did not accord with the output field in certain regions. To predict the full flow fields, it was necessary to take into account dissipative flow characteristics in two other quadrants: for low-output parallel flow (when there is still flow available from the pump of higher head when the ‘weaker’ pump's flow has been reduced to zero), that in the [+H, –Q] quadrant; and for high series flow (after the output head of the pump of lower maximum flow has been reduced to zero), that in the [–H, +Q] quadrant. This problem does not arise when the pumps have identical characteristics.

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