Experimental analysis of evacuated tube solar air heater (ETSAH) with inbuilt sensible thermal energy storage

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The hot air has a lot of applications like drying, space heating, desiccant air conditioning and desalination, which attracts the attention of researchers towards the system used for producing the hot air. In the present work, two different solar air heaters that is, double‐ends open evacuated tube based solar air heater (system 1) and single‐end open evacuated tube based solar air heater (system 2) are proposed and compared experimentally. The aperture area of each system is 4.687 m2 and operated under same weather conditions. The experiments are performed at three different mass flow rates of the process air that is, 153.21, 207.94, and 246.24 kg/h. The highest mean air temperature difference is 62.91 and 48.8°C for system 1 and system 2 respectively at mass flow rate of 153.21 kg/h. The highest mean energy and exergy efficiency obtained by the system 1 and system 2 are 81.55%, 6.80%, and 65.45% and 4.25% respectively. The present work is also compared with the work presented in literature and it is observed that double‐end open evacuated tube collector has significantly high energy and exergy efficiency with higher hot air temperature.

“…Thus, the overall exergy input to the ET-SAH is summation of exergy of available solar intensity and the exergy of heat stored by ETC. It is given as 18 :…”

Section: Exergy Analysismentioning

confidence: 99%

“…Thus, the total energy input to the ET‐SAH is the sum of heat provided by available solar intensity and the ETC. It is given as 18 :

Q_{italicinput} = (I_{italicavg} \times A_{c}) + {((), \frac{m C_{p} ∆ T_{italicETC}}{1800})}_{italicETC}

…”

Section: Thermal Analysismentioning

confidence: 99%

“…Thus, the overall exergy input to the ET‐SAH is summation of exergy of available solar intensity and the exergy of heat stored by ETC. It is given as 18 :

ϵ_{input} goodbreak= ({}, I_{avg} A_{c} ([], 1 goodbreak- \frac{4}{3} ((), \frac{T_{amb}}{T_{sun}}) goodbreak+ \frac{1}{3} {(\frac{T_{italicamb}}{T_{italicsun}})}^{4})) goodbreak+ ({}, \frac{m C_{p}}{1800} ((), ∆ T_{ETC} goodbreak- T_{amb} \ln \frac{T_{f, ETC}}{T_{i, ETC}}))

…”

Section: Thermal Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

° C

.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Experimental comparison of solar air heater based on single and double‐ends open evacuated tube collector

Tiwari,

Kumar

2023

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Experimental comparison of evacuated tube solar air heater based on energy and exergy analyses with environmental and economic (4‐E) study

Agrawal

Kumar

Parekh

2023

Self Cite

For the purpose of low‐medium air heating applications like timber seasoning, HVAC, agricultural & food drying, space heating and desalination, there is requirement of hot air. Solar air heaters are the promising systems to satisfy these requirements in a very inexpensive manner. Due to higher efficiency at higher operating temperature and lower cost, evacuated tube collectors (ETCs) are preferred for solar air heating. In this manuscript, the comparative parametric study of two similar sets of evacuated tube solar air heater (ETSAH) is performed. The comparison is based on energy & exergy analyses, and also presents the environmental and economic study (4E analyses). Each set is fabricated using mild steel (M.S.) along with 50 evacuated tubes with total collector area of 8.46 m2. The experimental investigations are made at diverse flow rates, with and without using conventional reflectors. Without incorporating any additional heat storage unit, the system provides average hot air temperature of 76.13°C when average solar intensity was 502.68 W/m2 during 11 h of operation from 09:00 to 20:00 h. ETC's absorber glass and the M.S. material was observed to have significant energy storage and discharge. The single set of ETSAH has mitigation of 89.20 tons with 2.05 years of energy payback period, which is significantly low as compared to its 20 years of lifespan. For the optimum system performance the cost of generated hot air is 0.00048 $/kg, which is considerably low.

Effect of operating parameters of desiccant wheel on the performance of solar desiccant dehumidifier

Kushwaha,

Kumar,

Choudhary

2024

To produce dry air, desiccant wheel is a very common choice now a day. However, it's crucial to utilize the desiccant wheel effectively. Therefore, in the present investigation, a numerical model is developed to identify the best operating conditions for a solar desiccant dehumidifier based on desiccant wheel and it is observed that the dehumidification capacity can be increased by simultaneously increasing the process air velocity and RPH of the desiccant wheel. A higher temperature of hot air for regeneration allows for a higher process‐to‐regeneration sector facial area ratio, which results in higher amount of dry air. After the mathematical investigation, the desiccant wheel is attached with solar air heater for experimental investigation. The solar air heater is based on both ends open evacuated tube collector, which is able to produce hot air at about 150°C at a mass flow rate of 143 kg/h. At this temperature the desiccant wheel shows remarkable dehumidification effectiveness of 0.61 with an average moisture removal of 0.0098 kgwp/kgda. The average thermal effectiveness and DCOP of the solar desiccant dehumidifier are observed to be 0.24 and 0.23, respectively.