Design of a Solar Air Heating Collector from Steel Cans

Numerous research works have examined the efficiency of both single- and double-pass solar air heaters. These investigations cover the pressure drop in ducts, flow phenomena, heat transfer enhancement, and solar air heater design. Recycled aluminum cans are used as the absorbing material in this project’s experimental work, which is based on an energy analysis of a solar air heating collector. The tops and bottoms of the cans will be drilled out, and they will be assembled into vertical columns through which air flows. The sun heats the cans with black paint. The air rising through the can’s columns absorbs the solar heat. A single-pass solar air heating collector with a single cover has been created. The effectiveness of the most important design and environmental parameters, such as mass flow rate and ambient temperature, on the model’s performance, was examined. Temperatures at the inlet and outlet, as well as thermal heat flow, were calculated. All of the can columns receive room air from a manifold at the bottom, and heated air is collected and distributed back to the room by a manifold akin to the one at the top of the collector. An efficient collector combines a large amount of heat transfer area from the cans to the air with uniform air distribution throughout the collector. The creation and testing of an effective single-glass air solar collector with an absorber plate composed of recyclable aluminum cans (RAC) are detailed in this project. This collector was created as a suggestion on how to construct air solar collector absorber plates at a reasonable cost by recycling recyclable materials. The collector’s absorber plate was made up of eight airflow channels with a circular cross-section made of 54 recyclable aluminum cans. Seven reusable cans, each with an absorptance of 0.903, were painted black using an opaque black paint that was widely available.

Introduction

Burning fossil fuels releases greenhouse gases (CO₂, SO₂, NO_x), increases air pollution and acid rain, depletes the ozone layer, and contributes to global warming. The expectation of a significant increase in the demand for heat and power in the future exacerbates the global issue. For various industries, heated air has a substantial energy requirement. The goal of developing solar air heaters is to decrease the need for traditional fuels.

The amounts of fossil fuel consumed by the residential and commercial sectors are higher. As a result, both residential and commercial buildings’ heating and cooling systems produce a significant amount of CO₂. Using renewable energy sources instead of fossil fuels can help lower the amount of energy needed to heat and cool buildings [1]. Solar energy is one of the many new energy sources that humans are using that is becoming more accessible and advantageous [2]. In many countries, solar collectors are a common way to warm water or air because they function as a blackbody, absorbing distant solar radiation from all over the world and converting it into thermal energy over an absorber plate [3]. Flatplate solar collectors, which use basic designs to transform energy, are widely used in industrial technologies [6], food dehydration and crop drying [5], and space heating [4]. Design parameters have been considered in numerous improved devices. Razika, along with others. The inclination angle for the absorption–convection heat transfer mechanism was examined in [7] and Al-Kayiem and Yassen [8]. El-Sebaii and Shalaby [10] and Das et al. [9] looked into the impact of employing absorber plates coated with different types of selective coating materials on collector performance. The collector thermal performances of solar air heaters with perforated glazing and varying inner collector colors were showcased by Vaziri et al. [11]. Based on energy and energy analysis, Fudholi et al. [12] and Gupta and Kaushik [13] developed a potential improvement for a solar collector.

A water pump to investigate the impact of the number of impeller blades on the pump performance, a solar water pump model to investigate the impact of the number of impeller blades on the pump performance, a basic S. P. P. model to investigate the impact of raising the boiler pressure on the efficiency of the model, and a Run of Libyan’s man-made river hydroelectricity model (LMR HEM) were all designed and investigated [14]–[17].

Low convective heat-transfer coefficients caused by a viscous laminar sub-layer in the turbulent boundary layer close to the absorber plate surface and a restricted heat-transfer area because of the capital cost are the primary drawbacks of using conventional solar collectors. It is possible to overcome these two limitations with turbulence promoters; to do this, the laminar sub-layer should be destroyed to facilitate efficient momentum exchange, and the heat transfer area should be expanded to improve thermal performance. The literature provides extensive documentation on how various techniques, such as extended heat-transfer area using v-grove flow channels [20], different fin shapes [21], thin ribs [22] and baffles [23], and destroyed laminar sub-layer using flow turbulence with vortex generators [24], [25], surface roughening on the absorber plate [26], packing wire mesh [27] and porous medium materials [28], and recycling operations [29], are used to achieve augmented heat transfer characteristics [18], [19].

In order to safeguard the component against failure, bending, and deformation, transient heat transfer axi-symmetric mathematical modeling has been developed to predict hardness, determine the lowest hardness point, and investigate the impact of radius on E-LHP of industrial quenched steel bar [30]–[38]. One type of heat exchanger that converts solar energy into heat is an air solar collector. Typically, they are employed as air heaters in conjunction with auxiliary heaters to provide building air conditioning and to heat air for drying agricultural products. One of the benefits of solar air heaters is that the fluid never freezes or boils. The low density, low thermal capacity, and low heat conductivity of air are, nevertheless, drawbacks [40]. Typically, an absorber, a transparent cover, and a case containing back insulation make up an air solar collector. While air circulates between the absorber plate and the thermal insulation, the transparent cover lowers heat losses in the direction of the front. Heat must be effectively transferred from the absorber to the flowing air in order to increase thermal efficiencies [45]. suggested changing the straightforward absorber flat plate for a solid matrix; these included the corrugated absorber [41], the fin-attached absorber plate [42], the V-corrugated absorber plate [46], the porous absorber plate [45], and the metal matrix absorber plate [44] that enhances thermal performance. All of the suggested absorber plates use brand-new, pure materials, which suggests that producing these extremely unique absorber plates will be expensive. Reference [43] stated that the primary obstacle to the widespread adoption of thermal solar systems is their high cost in comparison to traditional heating systems. The importance of the collector’s expenses is growing, and there is a clear need for less expensive collectors. This concept led to the construction of a crude air solar collector design that used easily recyclable materials for the absorber plate [39]. This collector’s extremely low efficiency was revealed by the thermal evaluation [46]. We made the decision to use recyclable materials to design and construct a new, more effective air solar collector in light of the prior experience. The design process, the newly designed air solar collector with an absorber plate composed of recyclable aluminum cans (RAC), the thermal performance assessment, and a comparison of the collector’s thermal efficiency with other collectors’ efficiencies with various absorber plate designs documented in the literature are all covered in this paper.

The Collector’s Design Process

In this work, the components of the experiment will be explained, as four wooden boards 90 cm long and 50 cm wide were used to form a box, as shown in Fig. 1.

Fig. 1. The collector’s system design box.

The box is punctured from the bottom with 8 equal holes for the passage of air from the bottom to the top, as shown in Fig. 2.

Fig. 2. The holes that require air to move from the bottom to the top.

Computer Cooling Fan 120 mm 12 V Delta AFB1212SH 1225 12025 120 × 120 × 25 mm 0.80 A, four pin arm is used to service the central units as shown in Fig. 3.

Fig. 3. The collector’s process design’s pin arms.

Whereas a 54-cola drink container was used, it was perforated from the bottom with four holes and three holes from the top for each piece, as shown in Fig. 4.

Fig. 4. Coca-Cola drink can.

The containers used are painted black due to the ability of the black color to absorb sunlight, as shown in Fig. 5.

Fig. 5. Coca-Cola drink cans are painted black.

After the coating process, the cans are arranged as eight columns and seven rows, as shown in Fig. 6.

Fig. 6. Eight columns and seven rows consider up the arrangement of the cans.

The collector was covered with a plastic glass cover at the front of the box with dimensions of 88 cm in height and 48 cm in width, as shown in Fig. 7.

Fig. 7. The collector’s cover was made of plastic glass.

Also from the components is a HY-1035 solar panel with specifications: 35 W is the maximum power (Pmax), 10 V is the maximum voltage (Vop), 3.5 A is the maximum current (Imp), 12 V is the open circuit voltage (Voc), and 3.85 A is the short circuit current (Isc).

Size is 580 × 360 × 17 mm, as shown in Fig. 8.

Fig. 8. HY-1035 solar panel.

The solar panel is connected to the fan to drive and move the air inside the collector, as shown in Fig. 9.

Fig. 9. The connected fan to the solar panel.

Results and Discussion

Calculation of the Cooling Load by Solar Radiation Low

$$\begin{array}{r}qs=a.shg.sc\end{array}$$

$$\begin{array}{r}a=d.h=0.054102m\times 0.1223m=0.0062\end{array}$$

$$\begin{array}{r}shg=0.887atu\end{array}$$

(1) $$\begin{array}{r}minimumsc=qs=54(0.00662\times 0.887\times 0.90)=0.267j\end{array}$$

where

gs – heat quantity

shg – solar heat gain coefficient

a – area

sc – shading coefficient

Calculation of the Cooling Load by Using Thermal Energy Low

$$\begin{array}{r}Q=m\times C_v\times \mathrm{\Delta }T\end{array}$$

$$\begin{array}{r}m=0.000429kg\times 54=0.023166kg\end{array}$$

The change in temperature at different times can be calculated from Table I and Fig. 10.

$$\begin{array}{r}{Q}_1=0.023166\times 718(50-33)=282J\end{array}$$

$$\begin{array}{r}{Q}_2=0.023166\times 718(57-37)=332J\end{array}$$

$$\begin{array}{r}{Q}_3=0.023166\times 718(58.6-39)=326J\end{array}$$

(2) $$\begin{array}{r}{Q}_4=0.023166\times 718(45.5-32)=224J\end{array}$$

Table I. The Out Temperature (°C) at Different Times of the First Day

Day	Date	Time	Air temperature	Out temperature
Friday	27/5/2022	9:00 am	33°C	50°C
		1:00 pm	37°C	57.2°C
		4:00 pm	39°C	58.6°C
		6:00 pm	32°C	45.5°C

Fig. 10. The out temperature (°C) at different times on the first day.

where

Q – thermal flow

m – air mass = 330 mL = 0.33L

C_v – specific net factor = 718 j/kg

ΔT – temperature change

Thermal flow (J) of the first day shown in Fig. 11.

1L – 1.3 g = 0.33 L × 1.3 g = 0.42 g

$$\begin{array}{r}\text{Q}=\text{m}\times {\text{C}}_{\text{v}}\times \mathrm{\Delta }\text{T}\end{array}$$

$$\begin{array}{r}{Q}_1=0.023166\times 718(97.4-31)=272J\end{array}$$

$$\begin{array}{r}{Q}_2=0.023166\times 718(53-41)=200J\end{array}$$

$$\begin{array}{r}{Q}_3=0.023166\times 718(44.6-38)=109J\end{array}$$

(3) $$\begin{array}{r}{Q}_4=0.023166\times 718(39-29)=166J\end{array}$$

$$\begin{array}{r}Q=m\times C_v\times \mathrm{\Delta }T\end{array}$$

$$\begin{array}{r}{Q}_1=0.023166\times 718(43-30)=218J\end{array}$$

$$\begin{array}{r}{Q}_2=0.023166\times 718(45-36)=149J\end{array}$$

$$\begin{array}{r}{Q}_3=0.023166\times 718(44.6-38)=216J\end{array}$$

(4) $$\begin{array}{r}{Q}_4=0.023166\times 718(41.4-29)=206J\end{array}$$

$$\begin{array}{r}\text{Q}=\text{m}\times {\text{C}}_{\text{v}}\times \mathrm{\Delta }\text{T}\end{array}$$

$$\begin{array}{r}{Q}_1=0.023166\times 718(43-30)=218J\end{array}$$

$$\begin{array}{r}{Q}_2=0.023166\times 718(45-36)=216J\end{array}$$

$$\begin{array}{r}{Q}_3=0.023166\times 718(44.6-38)=206J\end{array}$$

$$\begin{array}{r}{Q}_4=0.023166\times 718(41.4-29)=166J\end{array}$$

The out temperature at different times of the second day shown in Table II consequently the change in temperature can be determined as shown in Fig. 12 and Fig.13. showed the thermal, flow (J) of the second day shown.

Fig. 11. Thermal, flow (J) of the first day.

Table II. The Out Temperature (°C) at Different Times of the Second Day

Day	Date	Time	Air temperature	Out temperature
Saturday	28/5/2022	9:00 am	31°C	47.5°C
		1:00 pm	39°C	50°C
		4:00 pm	38°C	44.6°C
		6:00 pm	29°C	39°C

Fig. 12. The out temperature (°C) at different times of the second day.

Fig. 13. Thermal, flow (J) of the second day.

The out temperature at different times of the second day shown in Table III consequently the change in temperature can be determined as shown in Fig. 14 and Fig.15. showed the thermal, flow (J) of the third day shown.

Table III. The Out Temperature (°C) at Different Times of the Third Day

Day	Date	Time	Air temperature	Out temperature
Sunday	29/5/2022	9:00 am	30°C	47.4°C
		1:00 pm	33°C	45.6°C
		4:00 pm	33°C	46°C
		6:00 pm	29°C	41.9°C

Fig. 14. The out temperature (°C) at different times of the third day.

Fig. 15. Thermal, flow of the third day.

The out temperature at different times of the second day shown in Table IV consequently the change in temperature can be determined as shown in Fig. 16 and Fig.17. showed the thermal, flow (J) of the fourth day shown.

Table IV. The Out Temperature (°C) at Different Times of the Fourth Day

Day	Date	Time	Air temperature	Out temperature
Monday	30/5/2022	9:00 am	35°C	43°C
		1:00 pm	36°C	44°C
		4:00 pm	32°C	42.3°C
		6:00 pm	28°C	39.8°C

Fig. 16. The out temperature (°C) at different times of the fourth day.

Fig. 17. Thermal flow of the fourth day.

Conclusion

The results of this investigation show that the main objective of this project was to build a low-cost, straightforward solar air collector out of recycled materials and then examine and carry out any necessary improvements. A study was conducted to assess the thermal efficiency of an aluminum can solar air collector under different operating conditions. Measurements of the collector’s airflow and temperature, as well as other meteorological parameters like thermal flow, solar radiation, and outside temperature, were taken. Second, the heat balance is established in order to assess the collector’s performance. The internal pipe shape has been altered to create turbulent flow in order to maximize performance.

It was found that when the air velocity through the absorber tubes increases in tandem with the air mass flow rate, there is a significant increase in thermal efficiency. This notable improvement in thermal efficiency can be attributed to the heat transfer enhancer and the transition from a laminar to turbulent regime in the flow conditions.

The following techniques can improve the performance of an air solar collector: building a flow duct with minimal pressure losses; using a fan with a power-flow rate characteristic; using a cover with high transmittance and low absorptance and thermal conductivity; using a low-cost absorber with high absorptions and thermal conductivity.

In summary, the goals of this study were effectively accomplished.