An analytical expression for the instantaneous efficiency of a flat plate solar water heater and the influence of absorber plate absorptance and emittance

Roberts, D.E.; Forbes, Andrew

doi:10.1016/j.solener.2012.01.032

Cited by 21 publications

(6 citation statements)

References 12 publications

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“…However, it should be noted that the optical efficiency is affected by other parameters of a particular absorber application. Therefore, high selectivity does not necessarily indicate the best absorber [42]. For this reason, in the presented calculation of FM, by neglecting convection and conduction heat loss and following boundary conditions, it is assumed: 1000 W•m −2 incidence solar radiation (G), 80 • C operating temperature of the absorber (T A ), and 0 • C ambient temperature e.g., sky (T sky ).…”

Section: Spectral Optical Measurementsmentioning

confidence: 99%

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Preparation and Characterization of a Selective Polymer-Based Solar Absorber for Building Integration

2020

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Recent technological advances in solar absorber production may have created opportunities for new applications of these materials in buildings. A low-emissivity enhanced polymer-based absorber foil was developed and prototyped to demonstrate feasibility of the concept. This paper describes key development factors leading to a particular composition of the prototype and its testing, specifically spectroscopy measurements (both for shortwave and longwave regions) and environmental impact assessment of its production. It also provides comparison of the tested parameters with commercially available absorbers. The results show that the developed absorber has relatively good thermal emissivity (approx. 0.3), high solar absorption (0.95) and selectivity (3.2), and significantly lower (up to 98%) environmental impacts compared to the commercially available metal-based solar selective absorbers.

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Section: Spectral Optical Measurementsmentioning

confidence: 99%

“…Optical parameters. The performance data presented in Table 2 can be utilized to determine the efficiency of the compared absorbers in various solar thermal applications (e.g., solar thermal collectors in [30,42]). P1, S3, and R2 absorbers share the best solar absorbance (α λ = 0.95).…”

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confidence: 99%

Preparation and Characterization of a Selective Polymer-Based Solar Absorber for Building Integration

2020

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“…Fig. 2 displays the second design of solar heating systems, called forced circulation systems, which require a pump that circulates the water (Roberts and Forbes, 2012). The operation of the pump is monitored by an electronic system that rotates the pump when necessary (Ahmed, Daoud, et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

The Various Designs of Storage Solar Collectors: A Review

Ahmed

Algburi²,

Daoud

et al. 2022

Int. J. Renew. Energy Dev.

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The use of solar energy to heat water is the more critical application of solar energy. Researchers are trying to develop different methods to improve the efficiency of solar water heaters to meet the increasing demand for hot water due to global population growth. To reduce the cost and increase the efficiency of solar heaters, the solar collector and the storage tank are combined into one part, and this system is called solar storage collector. It can be defined as geometric shapes filled with water, painted black, and placed under the influence of sunlight to gain the largest amount of solar energy. This article presents the various designs of solar storage collector. This review showed that design variables and design shape significantly affect the efficiency of the solar heating system. Climate and operational factors also have a strong influence on the performance of solar heating. Furthermore, scientists and researchers have also used nanotechnology, solar cells, and mirrors to improve other stored solar collectors' performance. Finally, recently published articles indicate an increase in interest in improving the efficiency of solar storage collector by creating new designs that enhance the economic and practical viability.

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“…Furthermore, the study revealed that about 1480 GWh of electric energy could be saved by using SWH. Roberts and Forbes [9] reported that the majority of the solar heating industries are for water heating for domestic use. Their work showed that the prevalent type of collector used is the flat plate.…”

Section: Introductionmentioning

confidence: 99%

Decoupling the Monitoring of Solar Water Heaters and their Usage Profiles

Nwodo

Overen

Meyer

2021

Water

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South Africa is the most technologically advanced nation in Africa. However, the country is plagued with constant load shedding. The country receives about 2500 sunshine hours annually, with daily average irradiation levels of 4.5–6.5 kWh/m2. Despite these potentials, the use of electricity for domestic water heating is still prevalent in the country. The mass rollout of solar water heating (SWH) technologies in the low-cost housing sector across the country were met with massive failures. This study aims to assess the energy yield of a passive flat plate and an evacuated tube solar water heating system by evaluating the performance of these systems to address the energy crisis in South Africa. The flat plate (FP) and evacuated tube (ET) solar water heating systems were monitored for four days, characterised by varying sky conditions through instantaneous data measurement at 5 s. The parameters measured were water temperature, ambient temperature, irradiance at the plane of array, relative humidity, wind speed and direction. The results obtained show that a maximum irradiance of 1050 W/m2 was obtained on a clear day and corresponded to a hot water temperature of about 58 °C and 65 °C for the FP and ET, respectively. However, a cloudy day with a maximum irradiance of 400 W/m2 produced about 22 °C and 29 °C of hot water for the FP and ET, respectively. The results obtained in this study will guide stakeholders in the renewable energy sector towards employing SWH systems to replace or augment the electric geyser. Solar water heaters (SWH) can be used in the low-cost housing sector to provide hot water. Hence, the assessments in this study offer essential information for the deployment of these systems to reduce demand on the ailing South African electricity utility, Eskom, and mitigate climate change.

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An analytical expression for the instantaneous efficiency of a flat plate solar water heater and the influence of absorber plate absorptance and emittance

Cited by 21 publications

References 12 publications

Preparation and Characterization of a Selective Polymer-Based Solar Absorber for Building Integration

Preparation and Characterization of a Selective Polymer-Based Solar Absorber for Building Integration

The Various Designs of Storage Solar Collectors: A Review

Decoupling the Monitoring of Solar Water Heaters and their Usage Profiles

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