Employing Low-Concentration Photovoltaic Systems to Meet Thermal Energy Demand in Buildings

Abstract

This study evaluates the energy performance and efficiency of a low-concentration photovoltaic (CPV) system integrated with a phase change material (PCM), referred to as the CPV–PCM system, which stores and delivers thermal energy for building applications. A paraffin-based PCM with a melting point range of 58–60 °C was selected to align with typical building temperature requirements. The system was tested over three consecutive days in July at Al Ain, United Arab Emirates, under extreme climatic conditions (2100 W/m² solar irradiance, 35–45 °C ambient temperature), and its performance was compared to standard CPV and traditional tracked PV systems. The results demonstrate that PCM integration significantly enhances thermal regulation, reducing CPV peak temperatures by 38 °C (from 123 °C to 85 °C) and average temperatures by 22 °C (from 88 °C to 66 °C). The CPV–PCM system achieved a total energy efficiency of 60%, doubling that of standard CPV (30%) and tracked PV (25%), with cumulative electrical and thermal energy outputs of 370 Wh and 290 Wh, respectively. This dual electrical–thermal output enables the system to meet building heating demands, such as ~200–300 Wh/m² for domestic hot water and ~100–150 Wh/m² for space heating in United Arab Emirates winters, positioning it as a sustainable solution for energy-efficient buildings in arid regions. The findings underscore the advantages of PCM-based thermal control in CPV systems for hot climates, addressing gaps in prior studies focused on moderate conditions. Future research should explore long-term durability, optimized containment techniques, and alternative PCMs to further improve performance.

1. Introduction

Concentrated photovoltaics (CPVs) suffer from elevated operating temperatures, typically around 100 °C, which cause power losses of approximately 0.5% per °C above 25 °C and accelerate PV cell degradation [1,2]. To mitigate these issues, phase change materials (PCMs) have been explored for thermal management in photovoltaic (PV) systems, enabling excess heat storage and temperature regulation. For instance, a paraffin wax-based PCM housed in an aluminum container was integrated with a simulated PV cell, demonstrating effective thermal control and daytime heat storage [3]. This concept was advanced by incorporating PCM into an actual PV cell, forming a PV–PCM system that was tested indoors with a solar simulator, which showed significant heat storage and PV temperature reduction, suggesting PCM’s potential as a heat storage medium beneath PV panels [4].

The PV–PCM configuration was extended to outdoor testing across diverse climates. In Vehari, Pakistan, with a predominant cooling load, and Dublin, Ireland, with a heavy heating demand, PCMs such as CaCl₂·6H₂O and capric-palmitic acid were evaluated. In Vehari’s hot, stable climate (solar irradiance ~1000 W/m²), the system achieved a 13% power output increase and a 21 °C temperature reduction, compared to more variable conditions in Dublin (~760 W/m²) [5]. CaCl₂·6H₂O outperformed capric-palmitic acid, providing an additional 4 °C cooling and 3% power increase, underscoring the importance of selecting PCMs with melting points tailored to specific climates [6]. Further studies in moderate climates, such as Lisbon, Portugal, demonstrated maximum electrical and thermal efficiencies of 10% and 12%, respectively, using PCMs with lower melting points (e.g., 29 °C for CaCl₂·6H₂O), highlighting their suitability for cooler environments [7].

Building on these findings, a PV–PCM system was developed for the hot climate of the United Arab Emirates (United Arab Emirates), using a 6 cm-thick PCM layer with a 40 °C melting point. A year-long outdoor test showed that 5% of incoming solar energy was stored as thermal energy, reducing PV temperature by 10.5 °C and increasing electrical generation by 5.9% [8]. This configuration also reduced building heat gain, improving indoor cooling performance by 9.5% at peak and 7% on average, and PV power output by 7.2% at peak and 5% on average, by placing the PCM in an insulated container to simulate indoor conditions [9]. In the United Arab Emirates, PCM-integrated systems have shown promise for building heating applications, such as domestic hot water supply. A United Arab Emirates-based study utilized PCM-stored thermal energy for winter household water heating, recovering 41% of incoming solar radiation as thermal energy and boosting PV efficiency by 1.3% [10]. In another study, BIPV–PCM achieved a 12% reduction in panel temperature as compared to the reference panel, alongside a 10% increase in PV electrical efficiency [11]. Another study’s findings suggest that PCM can meet the heating requirements of buildings in the United Arab Emirates, such as water and space heating, while improving the thermal and electrical performance of PV systems, particularly in extreme climates where high-grade heat enhances PCM storage capacity [12].

Despite these advancements, challenges persist in non-concentrated PV–PCM systems, including limited thermal energy recovery [13,14] and PCM re-solidification issues in hot climates due to high nighttime ambient temperatures [4,10]. Comprehensive reviews suggest that PCM-based cooling can be cost-effective if thermal energy is utilized efficiently [14,15,16]. CPV systems, operating at higher temperatures due to concentrated solar input, demand more robust thermal management to prevent degradation and power loss [17]. However, the high-grade heat generated by CPV systems offers significant opportunities for thermal energy storage and utilization [18,19,20]. For instance, a CPV–PCM system in Al Ain, United Arab Emirates, using a paraffin-based PCM (58 °C melting point), achieved a 50 °C temperature reduction and 30% higher energy output than a reference CPV, optimized through a validated thermal model for melting and freezing cycles [12]. Another study conducted a performance evaluation of a CPV system integrated with various PCMs under the climatic conditions of Doha, Qatar. Among the evaluated materials, RT-60, characterized by a melting point close to 60 °C, yielded the highest system efficiency, reaching approximately 54.4%. The incorporation of this PCM contributed significantly to thermal regulation and energy storage, underscoring its effectiveness in enhancing CPV system performance in high-temperature environments and in utilizing of recovered thermal energy for domestic or commercial applications [21]. Similarly, a study in Macau using a tracked CPV–thermal (CPV–T) system with PCM RT27 (with a melting point of 27 °C) reported electrical, thermal, and overall efficiency gains of 10%, 5%, and 15%, respectively, under moderate irradiance (672 W/m²) [22]. Additional studies in hot climates, such as an inclined CPV–PCM system in Egypt (irradiance ~1000 W/m²), reported a 20 °C temperature drop but faced re-solidification challenges due to limited diurnal cooling [23].

Most prior research has focused on moderate or cooler climates [24,25,26,27,28], where lower irradiance and cooler nights facilitate PCM performance. In contrast, extreme climates maximize PCM’s thermal storage potential due to high-grade heat but pose unique challenges for cyclic operation. A critical knowledge gap remains in understanding CPV–PCM performance under extreme hot climates, such as Al Ain, United Arab Emirates, characterized by solar irradiance exceeding 2000 W/m² and ambient temperatures above 40 °C, which hinder PCM re-solidification and exacerbate CPV degradation [12,26]. Traditional cooling methods, primarily water-based, are not only resource-intensive but also impractical in arid regions with water scarcity, necessitating passive solutions such as PCM [2]. This study addresses this gap by experimentally evaluating a CPV–PCM system in Al Ain, United Arab Emirates, using a paraffin-based PCM (with a melting range of 58–60 °C) to achieve a 38 °C peak temperature reduction and 60% total energy efficiency, doubling the performance of traditional CPV (30%) and tracked PV (25%) systems. The novelty of this work lies in: (1) demonstrating CPV–PCM efficacy in extreme climates, where high irradiance and temperatures enhance thermal storage (290 Wh) for building heating applications, such as domestic hot water and space heating, while achieving a 38 °C temperature reduction and 60% total energy efficiency; (2) optimizing a 58–60 °C PCM to overcome re-solidification challenges, and (3) achieving 60% total energy efficiency, surpassing prior studies in moderate climates (e.g., 15% in Macau [22] and a 21 °C reduction in Vehari). These advancements position CPV–PCM systems as a sustainable solution for building energy demands in arid regions, reducing reliance on water-intensive cooling and conventional heating systems.

To achieve this, this study employed a CPV system integrated with a 40 L paraffin-based PCM (with a melting range of 58–60 °C) in a finned aluminum container, tested over three consecutive days in July at United Arab Emirates University’s Falaj Hazza Campus. The methodology involves characterizing PCM using the Temperature History Method (THM) and Differential Scanning Calorimetry (DSC), measuring temperature profiles with K-type thermocouples, and assessing electrical energy (via open-circuit voltage, short-circuit current, and fill factor) and thermal energy outputs using pyranometers and a NI-Compact DAQ system. The framework compares the CPV–PCM system against standard CPV and tracked PV systems, quantifying temperature reductions, power outputs, and efficiencies to validate PCM’s efficacy in extreme climates.

2. Methodology

To determine the melting range of the phase change material (PCM), both the Temperature History Method (THM) and Differential Scanning Calorimetry (DSC) were employed. The PCM was placed within a metal container with internal fins to improve heat conduction when the melting point was confirmed. This container was attached to the back side of the concentrated photovoltaic (CPV) panel. During the hottest month of July, the experimental campaign was conducted over three consecutive days, with minimal variation from day to day. Measuring the CPV module’s front surface temperature drop and assessing the resulting increases in thermal and electrical energy outputs were the main objectives. Temperature, voltage and current data were recorded at five-minute intervals using the CompactDAQ system and LabVIEW software sourced from National Instruments, Austin, TX, USA.

Key characteristics, such as fill factor (FF), short-circuit current (Isc), and open-circuit voltage (Voc), were used to assess electrical performance. As described in previous studies [5,9,29], thermal performance was evaluated by tracking the PCM temperature and computing thermal energy using the specific heat and latent heat formulae.

2.1. Material Characterization

To describe PCM on an application scale, THM is a tailored approach that can handle higher sample volumes of up to 40 g. In contrast, DSC is a standardized characterization technique that employs small sample sizes, usually 3–5 mg [6]. The thermophysical characteristics of homogeneous materials are measured using both methods [30]. A 45 g sample of melted PCM was placed in a 20 cm long glass test tube, with an internal diameter of 1.8 cm and a wall thickness of 0.08 cm, to characterize the PCM using THM (Figure 1). The PCM and a reference material (distilled water) were both placed in identical test tubes. To start the cooling and solidification process, the samples were heated and stabilized for a few minutes at 93 °C before being exposed to a lower ambient temperature of 21 °C.

Figure 1 shows the PCM’s phase transitions, with a solidification start point at 60 °C and an end point at 58 °C, aligning with the reported data that confirm RT-58′s melting/solidification range of 58–60 °C and latent heat (L = 160 kJ/kg). This range ensures efficient latent heat absorption, stabilizing PV temperatures near 58–60°. Paraffin wax cooled faster than distilled water in the liquid phase, reaching the solidification start point at 60 °C. Complete solidification was achieved at 58 °C. The DSC data, which show a melting onset temperature of 57.7 °C, are in agreement with these results.

Both characterization techniques verified that paraffin wax is an ideal match for CPV systems since it has a large heat storage capacity and is not supercooled. Its optimal melting point is between 58 and 60 degrees Celsius, which is much lower than the normal operating temperature of CPVs, which is around 100 degrees Celsius. Together with the parameters of other system components,

Table 1. The studies were carried out in a solid state using the thermophysical properties of bonding, metallic, and PCM materials.

Materials	Thickness d (m)	Area A (m2)	Thermal Conductivity $\mathbf{k} (\mathbf{W}/\mathbf{m}\mathbf{K}$)	Specific Heat Capacity ${\mathit{C}}_{\mathit{p}}$$(\mathbf{J}/\mathbf{k}\mathbf{g}\mathbf{K}$)	Density ρ $(\mathbf{k}\mathbf{g}/{\mathbf{m}}^3$)	Melting Point ${\mathit{T}}_{\mathit{m}}$(K)	Solidification Point ${\mathit{T}}_{\mathit{s}}$ (K)	Heat Storage Capacity Q = A.d.Cp.ρ (J/k)
PCM Paraffin Wax RT-58 [32]	0.5	0.08	0.2	2000	802	328 (55 °C)	334 (61 °C)	64,160
Aluminum [32]	0.003	1.533	202.4	871	2719	-	-	10,891
Insulation Glass Wool [33]	0.025	20	0.039	0.67	16	-	-	5.36
PV Layer 1 Glass [34]	0.003	0.1044	1.8	500	3000	-	-	469.8
PV Layer 2 ARC [34]	$100 \times {10}^{-9}$	0.1044	32	691	2400	-	-	0.017
PV Layer 3 PV Cells [34]	$225 \times {10}^{-6}$	0.1044	148	677	2330	-	-	37
PV Layer 4 EVA [34]	$500 \times {10}^{-6}$	0.1044	0.35	2090	960	-	-	104.7
PV Layer 5 Rear contact [34]	${10\times 10}^{-6}$	0.1044	237	900	2700	-	-	2.5
PV Layer 6 Tedlar [34]	0.0001	0.1044	0.2	1250	1200	-	-	15.6

summarizes additional thermophysical characteristics acquired from technical-grade paraffin PCM (RT 60) provided by Rubitherm, Berlin, Germany [31].

2.2. Experimental Setup

The experimental setup was designed to evaluate the thermal and electrical performance of a CPV–PCM system under extreme hot climate conditions in Al Ain, United Arab Emirates, with results compared against standard CPV and tracked PV systems. The setup and test procedure involved the following steps:

• Three monocrystalline PV modules, each measuring 29 cm × 36 cm and rated at 10 W with 15% efficiency, were positioned under a PMMA Fresnel lens concentrator (800 mm focal length, 1 m² aperture). The modules were installed at United Arab Emirates University’s Falaj Hazza Campus with a 24° tilt aligned to the local latitude (24.1° N) and used a dual-axis tracking system to ensure optimal solar exposure. Two modules were placed 360 mm below the lens and were exposed to focused sunlight over a 36 cm circular area, achieving an average concentrated irradiance of 2100 W/m², compared to 760 W/m² for tracked PV.
• A 40 L paraffin-based PCM (RT-58, with a melting range of 58–60 °C) was integrated into a 3-mm-thick aluminum (1050 A) container with internal fins to enhance heat conduction (thermal conductivity of 0.039 W/m·K). The container was insulated with a 2.5 cm-thick layer of glass wool and attached to the backside of the CPV module using epoxy resin adhesive for effective thermal contact. The PCM’s thermophysical properties are summarized in Table 1.
• Experiments were conducted over three consecutive days in July, with minimal day-to-day variation. Measurements were taken at 5-min intervals using calibrated K-type thermocouples (±1.5 °C, Class 1 accuracy) to monitor PV front and rear surfaces and PCM temperatures (front, middle, and back layers within the 40 L container). Three self-powered pyranometers (Apogee SP-110, ±5% calibration uncertainty) sourced from Apogee Instrument, Logan, UT, USA; measured solar irradiance on non-concentrated PV and CPV surfaces. Ambient temperature (35–45 °C) was monitored using a Star meter weather station (WS1041, ±1% accuracy). Data were collected via a NI-Compact DAQ system (9178, ±0.02% accuracy), as shown in Figure 2.
• Electrical performance was assessed by measuring open-circuit voltage (Voc) and short-circuit current (Isc) using NI-Analogue modules (9221 for voltage, ±0.25%; 9227 for current, ±0.01%), with a fill factor (FF = 0.72) sourced from PV catalog data, as per Equation (1). Thermal performance was evaluated using PCM temperature profiles and specific/latent heat formulae, as described in [5,7], to quantify heat storage and temperature reduction.
• All equipment (the weather station, pyranometers, thermocouples, DAQ, and the tracking system) was thoroughly examined and confirmed operational before testing. The measurement uncertainties are detailed in

  Table 2. Accuracy and measurement ranges of the instruments used in temperature, weather, PV performance, and data collection tests [26].

  Measurement Parameter	Device	Model No.	Measurement Range	Accuracy
  Solar radiation	Apogee Pyranometer [34]	SP–110	-	±1%
  Ambient temperature	Star meter weather station [35]	WS1041	−40–60 °C	±1%
  Data acquisition	NI-Compact DAQ [36]	9178	-	±0.02%
  Current	NI-Analogue module [36]	9227	5–20 A	±0.01%
  Voltage	NI-Analogue module [36]	9221	−60–60 V	±0.25%
  Temperature	NI-Analogue module [36]	9213	−75–250 °C	±1%

  .

3. Results and Discussion

Solar irradiance energy was recorded over three consecutive peak summer days in Al Ain, United Arab Emirates, for both tracked PV and concentrated PV (CPV) systems. For all arrangements, solar radiation intensity peaked around midday, as illustrated in Figure 2, but at notably different strengths. The CPV system obtained a significantly higher average irradiance of 2100 W/m², indicating an optical concentration factor of about three. In contrast, the tracked PV system received an average of only 760 W/m² between 9:00 and 17:00. The information shown in Figure 3 was essential for creating a suitable PCM containment system that uses 58 °C melting paraffin wax to support thermal energy storage and CPV cooling.

3.1. Data and Uncertainty Analysis

Data analysis involved calculating electrical and thermal performance metrics to quantify the CPV–PCM system’s efficacy. Electrical power (Pe) was computed using Equation (1).

Pe = V_oc × I_sc × FF

(1)

V_oc and I_sc were measured via NI-Analogue modules (±0.25% and ±0.01% accuracy, respectively) and FF = 0.72 was measured from PV catalog data. Thermal performance was evaluated using PCM temperature profiles and specific/latent heat formulae, as described in [5,7], to quantify heat storage and temperature reduction.

Total energy efficiency (η) was determined using Equation (2).

η = Qtot/SR

(2)

where Qtot is the sum of electrical and thermal energy and SR is the solar radiation input measured by the pyranometer. Uncertainty analysis, based on Table 2, accounted for instrumentation errors: thermocouples (±1.5 °C), pyranometers (±5%), DAQ (±0.02%), current (±0.01%), and voltage (±0.25%). The propagated uncertainty for electrical power was ±2.5%, calculated using partial derivatives of Equation (1). The thermal energy uncertainty was ±3%, considering thermocouple accuracy and PCM property variations (±5% for specific heat [29]). Total efficiency uncertainty was ±4%, combining electrical and thermal errors. These analyses ensure the reliability of reported results.

Figure 4 evaluates and contrasts the observed PCM temperatures of the average PCM throughout a summer day, specifically for the middle layer, back layer, and front layer (3 cm within the PCM from the front and back).

The findings shown in Figure 4 determine that the PCM was in its solid phase at the start of the day, as the starting PCM temperature (T_PCM) was 37 °C, which is significantly lower than the melting point (T_m) of 58 °C. TPCM rose quickly as the PCM started to absorb solar energy, until it approached the T_m, at which point the rate of temperature rise halted and melting began. The front surface underwent this phase transition at 8:30, the middle layer at 10:30, and the back layer at 11:30. Due to the high intensity of sun radiation, the PCM kept absorbing heat until 16:00. The solidification starts point (T_s) at 62 °C was reached at 18:00, when the cooling rate slowed, signifying the release of latent heat and the start of PCM solidification. After 16:00, the T_PCM started to drop precipitously. Due to the high ambient temperature (T_amb) in July, which hindered heat transfer from the melted PCM to the ambient air at night, the results indicate that the PCM completely melted in 9 h but took more than 14 h to solidify throughout the night.

The temperature profiles on the front surface of the concentrated PV, tracked PV, and concentrated PV–PCM systems for three summer days in July are shown in Figure 5.

With a peak temperature of 57 °C and an average daily value of 47 °C, the monitored PV system showed the lowest temperatures, according to the results. The CPV without PCM, on the other hand, saw noticeably higher temperatures, peaking at 123 °C and averaging 88 °C during the day. A PV temperature drop of 83 °C and an average temperature drop of 38 °C were the outcomes of successful heat absorption, evidenced by the addition of PCM to the CPV system.

The PCM would not melt in the absence of solar radiation, as indicated by the ambient temperature (T_amb) continuously staying below the PCM liquidus temperature (TL) of 61 °C during the day. On the other hand, T_amb stayed below the PCM solidification temperature (Ts) of 58 °C at night, suggesting that the PCM would solidify naturally by releasing heat into the surrounding air.

The transient electrical energy produced by the concentrated PV, tracked PV, and concentrated PV–PCM systems on three consecutive summer days in July is shown in Figure 6.

The tracked PV panel generated the lowest average electrical output of 13 W, as shown in Figure 6; however, with the use of CPV, this power increased to 40 W. The average power efficiency (Pe) was further improved by PCM integration to 43.5 W, representing an approximately 8% improvement. Remarkably, the addition of PCM to the CPV system resulted in a decrease in TPV (as illustrated in Figure 3). This, in turn, caused a rise in PV voltage, which subsequently led to an increase in power efficiency (Pe).

The cumulative electrical, thermal, and total energy outputs for the tracked PV, CPV, and CPV–PCM systems are shown in Figure 7(A), (B), and (C), respectively.

The tracked PV, CPV, and CPV–PCM systems generated 115 Wh, 350 Wh, and 370 Wh of cumulative electrical energy, respectively, as shown in Figure 7A. This suggests that the cooling of CPV by PCM resulted in a minor increase in electrical energy output. Up to the peak time, the PV, CPV, and CPV–PCM systems produced 20 Wh, 50 Wh, and 290 Wh of thermal energy, respectively, as shown in Figure 7B. In addition to the increases in electrical energy, the CPV–PCM system’s noticeably larger thermal energy production highlights the advantages of incorporating PCM into the CPV system for energy storage. Figure 7C illustrates how the total energy output was determined by adding the cumulative electrical and thermal energy values.

Figure 8 shows the energy efficiency (η) attained by the CPV, CPV–PCM, and tracked PV systems. As anticipated, the CPV system (30%) and the tracked PV system (25%) had the lowest energy efficiency, respectively. Due to the PCM’s capacity to store thermal energy, the CPV–PCM system experienced a notable increase in efficiency, reaching 60%.

3.2. Comparative Performance Analysis

The CPV–PCM system integrates phase change material to enhance performance over standard CPV and tracked PV systems, particularly in temperature regulation, electrical power, thermal energy storage, and overall efficiency, with significant potential for building heating applications, as detailed in Figure 5, Figure 6, Figure 7 and Figure 8.

The CPV–PCM system reduced peak operating temperatures by 38 °C (from 123 °C in CPV to 85 °C) and average temperatures by 22 °C (from 88 °C to 66 °C) under extreme climatic conditions (2100 W/m² solar irradiance, 35–45 °C ambient), compared to tracked PV’s peak of 57 °C and average of 47 °C (Figure 5) under normal climatic conditions (1000 W/m², 20–25 °C). This cooling effect, driven by PCM’s heat absorption (290 Wh, Figure 7B), mitigates thermal degradation, enhancing PV cell longevity in extreme climates.

The CPV–PCM system achieved an average electrical power of 43.5 W, an 8% improvement over CPV’s 40 W and a 234% increase over tracked PV’s 13 W (Figure 6). The cumulative electrical energy over three days was 370 Wh for CPV–PCM, compared to 350 Wh for CPV and 115 Wh for tracked PV (Figure 7A). The PCM’s temperature regulation increased open-circuit voltage (Voc), boosting power efficiency, as per Equation (1).

The CPV–PCM system generated 290 Wh of thermal energy, significantly higher than CPV’s 50 Wh and tracked PV’s 20 Wh (Figure 7B). The paraffin-based PCM (RT-58, with a melting range of 58–60 °C) efficiently stored high-grade heat from concentrated solar input, making it suitable for building heating applications, such as domestic hot water or space heating in United Arab Emirates winters.

The CPV–PCM system attained a total energy efficiency of 60%, doubling that of CPV (30%) and tracked PV (25%) (Figure 8). This was calculated using Equation (2): η = Qtot/SR, where Qtot includes electrical and thermal energy and SR is the solar radiation input (2100 W/m² for CPV, 760 W/m² for tracked PV). The high efficiency highlights the system’s ability to utilize both energy outputs effectively.

The CPV–PCM system’s 290 Wh thermal energy output meets significant portions of building heating demands, such as domestic hot water (~200–300 Wh/m² daily in United Arab Emirates winters) or space heating (~100–150 Wh/m² for small rooms). Unlike standard CPV (50 Wh) and tracked PV (20 Wh), the CPV–PCM system provides a sustainable solution for arid regions, reducing reliance on conventional heating systems. The 38 °C temperature reduction also enhances electrical efficiency, making CPV–PCM ideal for integrated building energy systems.

4. Conclusions

This study demonstrates the efficacy of a concentrated photovoltaic (CPV) system integrated with a paraffin-based phase change material (PCM, RT-58) for enhancing energy efficiency and thermal management in extreme climatic conditions (Al Ain, United Arab Emirates, 2100 W/m², 35–45 °C). The CPV–PCM system, tested over three days, achieved a peak temperature reduction of 38 °C (from 123 °C to 85 °C) and an average reduction of 22 °C (from 88 °C to 66 °C) compared to standard CPV. The internally finned aluminum container (RT-58) optimized heat transfer, enabling efficient phase transitions within the 58–60 °C range, confirmed using the Temperature History Method (THM).

The CPV–PCM system outperformed non-concentrated (tracked) PV and standard CPV, achieving a total energy efficiency of 60% (versus 25% and 30%, respectively, Figure 8), with cumulative electrical and thermal outputs of 370 Wh and 290 Wh (Figure 6 and Figure 7). These results, driven by the PCM’s latent heat absorption, highlight its suitability for building energy applications, meeting heating demands of ~200–300 Wh/m² for hot water and ~100–150 Wh/m² for space heating in United Arab Emirates winters. Compared to prior studies [5,7,10,12], the system’s performance in high-irradiance environments addresses a critical gap in sustainable solar energy solutions.

The finned container design, with high-conductivity aluminum and optimized fin spacing, ensured effective thermal regulation, reducing PV degradation and enhancing electrical output. However, future research should focus on long-term durability testing under cyclic thermal loads, optimizing fin configurations for higher heat transfer rates, and exploring PCMs with higher latent heat or broader phase change ranges to further improve performance. These advancements will strengthen the CPV–PCM system’s viability for widespread adoption in energy-efficient building designs in hot climates.