Effects of thermal mass and flow rate on forced-circulation solar hot-water system: Comparison of water-in-glass and U-pipe evacuated-tube solar collectors

Solar Energy ◽  
2013 ◽  
Vol 98 ◽  
pp. 290-301 ◽  
Author(s):  
Yan Gao ◽  
Qunli Zhang ◽  
Rui Fan ◽  
Xinxing Lin ◽  
Yong Yu
Keyword(s):  
Flow Rate ◽  
Water System ◽  
Hot Water ◽  
Thermal Mass ◽  
Solar Collectors ◽  
Forced Circulation ◽  
Evacuated Tube

Evacuated Tube Heat Pipe Solar Collectors Applied to Recirculation Loop in a Federal Building: SSA Philadelphia

Solar Energy ◽  
2004 ◽  
Author(s):  
Andy Walker ◽  
Fariborz Mahjouri ◽  
Robert Stiteler
Keyword(s):  
Solar Energy ◽  
Heat Pipe ◽  
Heat Loss ◽  
Heating System ◽  
Hot Water ◽  
Solar Array ◽  
Solar Collectors ◽  
Water Heating ◽  
Evacuated Tube ◽  
Recirculation Loop

This paper describes design, simulation, construction and measured initial performance of a solar water heating system (360 Evacuated Heat-Pipe Collector tubes, 54 m2 gross area, 36 m2 net absorber area) installed at the top of the hot water recirculation loop in the Social Security Mid-Atlantic Center in Philadelphia. Water returning to the hot water storage tank is heated by the solar array when solar energy is available. This new approach, as opposed to the more conventional approach of preheating incoming water, is made possible by the thermal diode effect of heat pipes and low heat loss from evacuated tube solar collectors. The simplicity of this approach and its low installation costs makes the deployment of solar energy in existing commercial buildings more attractive, especially where the roof is far removed from the water heating system, which is often in the basement. Initial observed performance of the system is reported. Hourly simulation estimates annual energy delivery of 111 GJ/year of solar heat and that the annual efficiency (based on the 54 m2 gross area) of the solar collectors is 41%, and that of the entire system including parasitic pump power, heat loss due to freeze protection, and heat loss from connecting piping is 34%. Annual average collector efficiency based on a net aperture area of 36 m2 is 61.5% according to the hourly simulation.

scholarly journals MEASUREMENT OF THE EFFICIENCY OF EVACUATED TUBE SOLAR COLLECTORS UNDER VARIOUS OPERATING CONDITIONS

2012 ◽  
Vol 7 (3) ◽  
pp. 114-130 ◽  
Author(s):  
S. E. Zubriski ◽  
K. J. Dick
Keyword(s):  
Environmental Conditions ◽  
Operating Conditions ◽  
Hot Water ◽  
Heat Transfer Fluid ◽  
Operating Efficiency ◽  
Space Heating ◽  
Solar Collectors ◽  
Auxiliary Equipment ◽  
Evacuated Tubes ◽  
Evacuated Tube

The operating efficiency of evacuated tubes themselves under varying environmental conditions and installation scenarios, independent of water and space heating auxiliary equipment, are not readily available values. Further, Manitoba specific data has not been established. The purpose of this research program was to measure the efficiency of evacuated tube solar collectors under various operating conditions including: the angle of inclination towards the incident solar radiation, heat transfer fluid flow rate, glazing installation, and number of evacuated tubes. The operating conditions and configurations were chosen to represent realistic or probable installation scenarios and environmental conditions. Furthermore, the research aimed to identify the suitability of evacuated tube solar collectors to each of the scenarios. These design values are of use for appropriate sizing of water or space heating systems, system configuration and optimization, and calculation of return on investment. The scope of the research project was limited to the efficiency of various configurations of a 32-tube panel, not the entire solar domestic hot water or space heating system. Thus, factors such as heat loss in the tubing, solar storage tank, and heat exchanger efficiency were not investigated. The findings indicated that efficiency varied by approximately 5% between the different collector configurations, as observed from the overlay graph of results. When the efficiency of a collector is considered within a system it is proposed that effectiveness may be a better measure of overall performance.

Research at the Building Research Establishment into the applications of solar collectors for space and water heating in buildings

1980 ◽  
Vol 295 (1414) ◽  
pp. 403-414
Keyword(s):  
Solar Collector ◽  
Water System ◽  
Cost Effective ◽  
Heating System ◽  
Field Studies ◽  
Hot Water ◽  
Solar Collectors ◽  
Water Heating ◽  
Actual Performance ◽  
Low Efficiency

A completed study of a solar hot water heating system installed in a school showed an annual average efficiency of 15%, the low efficiency largely caused by the unfavourable pattern of use in schools. Field studies, in 80 existing and 12 new houses, of a simple domestic hot water system have been initiated to ascertain the influence of the occupants on the actual performance of solar collector systems. The development of testing methods of solar collectors and solar water heating systems is being undertaken in close collaboration with the B.S.I. and the E.E.C. Solar space heating is being investigated in two experimental low energy house laboratories, one using conventional solar collectors with interseasonal heat storage and the other a heat pump with an air solar collector. Studies of the cost-effectiveness of solar collector applications to buildings in the U.K. show that they are far less cost-effective than other means of conserving energy in buildings.

Experimental Daily Energy Performance of Flat Plate and Evacuated Tube Solar Collectors

2009 ◽  
Author(s):  
Enrico Zambolin ◽  
Davide Del Col ◽  
Andrea Padovan
Keyword(s):  
Solar Energy ◽  
Flat Plate ◽  
Energy Performance ◽  
Hot Water ◽  
Solar Collectors ◽  
Input Output ◽  
Evacuated Tube Collector ◽  
Daily Energy ◽  
Radiation Test ◽  
Evacuated Tube

New comparative tests on different types of solar collectors are presented in this paper. Tests have been performed at the solar energy conversion laboratory of the University of Padova. Two standard glazed flat plate collectors and one evacuated tube collector are installed in parallel; the evacuated collector is a direct flow through type with external CPC (compound parabolic concentrator) reflectors. The present test rig allows to make measurements on the flat plate, on the evacuated collector or on both simultaneously, by simply acting on the valves to modify the circuit. In this paper measurements of the performance of the evacuated tube collector and flat plate collectors working at the same conditions are reported. Efficiency in stationary conditions is measured following the standard EN 12975-2 [1] and it is compared with the input/output curves measured for an entire day. The main purpose of the present work is to characterize and to compare the daily energy performance of the two types of collectors. An effective mean for describing and analyzing the daily performance is the so called input/output diagram, in which the collected solar energy is plotted against the daily incident solar radiation. Test runs have been performed in several conditions to reproduce different conventional uses (hot water, space heating, solar cooling).

scholarly journals HEATING WATER IN A HOT WATER SYSTEM USING SOLAR COLLECTORS

2020 ◽  
Author(s):  
L. Lipnitski ◽  
A. Khamitsevich ◽  
A. Butko
Keyword(s):  
Water System ◽  
Hot Water ◽  
Solar Collectors ◽  
Heating Water

scholarly journals EXPERIMENTAL STUDY OF FLAT PLATE SOLAR COLLECTORS WITH VARIOUS FLOW RATE OF WATER

2017 ◽  
Vol 5 (10) ◽  
pp. 112-116
Author(s):  
Anupras Shukla ◽  
Pushpraj Singh
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Flow Rate ◽  
Hot Water ◽  
Circular Pipe ◽  
Solar Water Heater ◽  
Solar Collectors ◽  
Flexible Pipe ◽  
Water Heater ◽  
Solar Water

In this paper, we are studying about solar water heater. The solar water heater are consisting of several components such as circular pipe, flexible pipe, and metallic container for water and circulating pump. We are analyzed the outlet temperatures of hot water using of various flow rate (in liters/ Minutes).

scholarly journals Energy efficiency of multi-apartment residential houses with individual heat supply

2020 ◽  
Vol 212 ◽  
pp. 01011
Author(s):  
Vladimir Melnikov ◽  
Uladzimir Navaseltsau ◽  
Dzina Navaseltsava
Keyword(s):  
Water Supply ◽  
Flow Rate ◽  
Thermal Energy ◽  
Water System ◽  
Hot Water ◽  
Water Supply Systems ◽  
Hydraulic Systems ◽  
Circulation Mode ◽  
Hot Water Supply ◽  
Internal Networks

Centralized hot water systems widely used in Russia and Belarus are characterized by a considerable length and branching which inevitably leads to increased heat losses and to an unstable hydraulic system. The operation of the domestic hot water system in the circulation mode can be characterized by several parameters; one of which is the specific ratio of the cost of thermal energy for heating a cubic meter of hot water. The parameter is often regulated by law in Russia; exceeding this parameter is considered as administrative violation. The aim of the research is to determine the design and actual costs of thermal energy for hot water supply (hot water heating) and their comparison, analysis of the data obtained. The methodology for determining the design and real costs of thermal energy for hot water supply was to study the operation of the hot water supply system of a residential 144-apartment 9-storey building. The research showed that the actual circulating flow rate is much less than the calculated circulating flow rate. The authors note that in order to optimize the standard for heating a cubic meter of water it is necessary to observe the calculated circulation modes. This will require stabilization of the hydraulic systems of both the external and internal networks which is a difficult but feasible task. The research results are supposed to be taken into account when setting up existing hot water supply systems.

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