scholarly journals Thermal Performance Representation and Testing of Air Solar Collectors

1988 ◽  
Vol 110 (2) ◽  
pp. 74-81 ◽  
Author(s):  
M. A. Bernier ◽  
E. G. Plett
Keyword(s):  
Uncertainty Analysis ◽  
Thermal Performance ◽  
Atmospheric Pressure ◽  
Leakage Rate ◽  
Solar Collectors ◽  
The Third ◽  
Enthalpy Balance ◽  
Gage Pressure ◽  
Storage Type ◽  
Plate Type

The thermal performance of a plate-type air collector was evaluated experimentally. Tests were performed at the two ASHRAE Standard 93-1986 recommended flowrates and at a variety of inlet gage pressures to cover the three possible cases of collector leakage (inward, outward, inward-outward). These tests show that the thermal performance of air collectors depends on flowrate and inlet gage pressure (or the associated leakage rate). If the collector is used at an inlet gage pressure near atmospheric pressure as is often the case in the no-storage type of systems, then it is recommended to test the collector at an inlet gage pressure of zero. For collectors operating at various inlet gage pressures it is suggested to test them at three inlet gage pressures. As for the test flowrate, the present work confirmed the results of other studies and emphasizes the need to test the collectors at the design flowrate. Three methods of thermal performance representation were used and compared: One method bases the efficiency on the inlet flowrate, another on the outlet flowrate, and the third involves an overall enthalpy balance. When plotted in the classic way, that is, η vs. (Ti − Ta)/G the three methods exhibit significant differences, especially for the inward leakage case. An uncertainty analysis on the data obtained for this study indicates that for the inward leakage case, unacceptable uncertainties occur at high values of (Ti − Ta)/G.

INFLUENCE OF WORKING FLUID ON THERMAL PERFORMANCE OF THERMOSYPHONS FOR APPLICATION IN HIGH PRESSURE VACUUM TUBE SOLAR COLLECTORS

2020 ◽  
Author(s):  
Guilherme Antonio Bartmeyer ◽  
Victor Vaurek Dimbarre ◽  
Pedro Leineker Ochoski Machado ◽  
PAULO HENRIQUE DIAS DOS SANTOS ◽  
Thiago Antonini Alves
Keyword(s):  
High Pressure ◽  
Thermal Performance ◽  
Working Fluid ◽  
Solar Collectors ◽  
Vacuum Tube

Vapour-liquid equilibrium in the isobutyl formate-isobutyl alcohol and n-butyl formate-isobutyl alcohol systems at atmospheric pressure

1979 ◽  
Vol 44 (12) ◽  
pp. 3501-3508 ◽  
Author(s):  
Jan Linek
Keyword(s):  
Experimental Data ◽  
Fourth Order ◽  
Atmospheric Pressure ◽  
Isobutyl Alcohol ◽  
Liquid Equilibrium ◽  
The Third

Isobaric vapour-liquid equilibria in the isobutyl formate-isobutyl alcohol and n-butyl formate-isobutyl alcohol systems have been measured at atmospheric pressure. A modified circulation still of the Gillespie type has been used for the measurements. The experimental data have been correlated by means of the third- and fourth-order Margules equations.

scholarly journals An experimental study of the thermal performance of the square and rhombic solar collectors

2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 487-494 ◽  
Author(s):  
Aminreza Noghrehabadi ◽  
Ebrahim Hajidavaloo ◽  
Mojtaba Moravej ◽  
Ali Esmailinasab
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Solar Collectors ◽  
Heating Systems ◽  
Solar Water Heating

Solar collectors are the key part of solar water heating systems. The most widely produced solar collectors are flat plate solar collectors. In the present study, two types of flat plate collectors, namely square and rhombic collectors are experi?mentally tested and compared and the thermal performance of both collectors is investigated. The results show both collectors have the same performance around noon (?61%), but the rhombic collector has better performance in the morning and afternoon. The values for rhombic and square collectors are approximately 56.2% and 53.5% in the morning and 56.1% and 54% in the afternoon, respectively. The effect of flow rate is also studied. The thermal efficiency of rhombic and square flat plate collectors increases in proportion to the flow rate. The results indicated the rhombic collector had better performance in comparison with the square collector with respect to the mass-flow rate.

scholarly journals Thermal Performance of Solar Collectors with EPDM Absorber Plates

1988 ◽  
Vol 41 (4) ◽  
pp. 623
Author(s):  
MJ O'Keefe ◽  
JLA Francey
Keyword(s):  
Experimental Study ◽  
Thermal Resistance ◽  
Flat Plate ◽  
Heat Loss ◽  
Thermal Performance ◽  
Critical Value ◽  
Solar Collectors ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
High Thermal Resistance

An experimental study of flat-plate solar collectors using ethylene, propylenediene monomer (EPDM) absorber plates is descn"bed. In spite of the high thermal resistance of this material the performance is found to compare well with metal absorbers and to be in agreement with the Hottel-Whillier-Bliss equation. There is, however, an observed increase in the heat loss coefficient for mass flow rates below a critical value.

Study on the thermal performance of a novel cavity receiver for parabolic trough solar collectors

2018 ◽  
Vol 222 ◽  
pp. 790-798 ◽  
Author(s):  
Hongbo Liang ◽  
Chunguang Zhu ◽  
Man Fan ◽  
Shijun You ◽  
Huan Zhang ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Solar Collectors ◽  
Parabolic Trough

A Numerical Model for Thermal Performance of an Unglazed Transpired Solar Collector

2011 ◽  
Author(s):  
Saeed Moaveni ◽  
Patrick A. Tebbe ◽  
Louis Schwartzkopf ◽  
Joseph Dobmeier ◽  
Joseph Gehrke ◽  
...  
Keyword(s):  
Numerical Model ◽  
Air Temperature ◽  
Thermal Performance ◽  
Solar Collector ◽  
Energy Savings ◽  
Ambient Air ◽  
Solar Collectors ◽  
Heating Unit ◽  
Plate Temperature ◽  
Building Wall

In this paper, we will present a numerical model for estimating the thermal performance of unglazed transpired solar collectors located on the Breck School campus in Minneapolis, Minnesota. The solar collectors are installed adjacent to the southeast facing wall of a field house. The collectors preheat the intake air before entering the primary heating unit. The solar collector consists of 8 separate panels (absorber plates). Four fans are connected to the plenum that is created by the absorber plates and the adjoining field house wall. All fresh air for the field house is provided by the solar collectors before being filtered and heated by four, independent two stage natural gas fired heaters. Moreover, the following data were collected onsite using a data acquisition system: indoor field house space temperature, ambient air temperature, wind speed, wind direction, the plenum exit air temperature, the absorber plate temperature, and the air temperatures inside the plenum. The energy balance equations for the collector, the adjacent building wall, and the plenum are formulated. The numerical model is used to predict the air temperature rise inside the plenum, recaptured heat loss from the adjoining building wall, energy savings, and the efficiency of the collectors. The results of the numerical model are then compared to the results obtained from the onsite measurements; which are in good agreement. The model presented in this paper is simple yet accurate enough for architects and engineers to use it with ease to predict the thermal performance of a collector.

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