Hospitals and health facilities are found in every city worldwide and often have similar utilities or engineering, mechanical, and electrical plumbing services. Two main mechanical systems in healthcare facilities are heat, ventilation, air conditioning, and domestic water. These systems supply healthcare facilities with air within specific controlled variables: temperature and humidity. They are subject to strict indoor air quality standards such as The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). Similarly, hot and cold domestic water is subjected to strict standards and regulations that control variables such as temperature and chemical dosing. In some cases, a unique water application requires further quality control of water that can only be obtained through water deionizers and reverse osmosis systems. Other mechanical systems which are typically found in healthcare facilities are not related to the results of this study and will not be highlighted. On the other hand, electrical systems, such as backup generators and uninterruptable power supply, are two of the key systems that will be highlighted in this study.

The engineering services systems found in health facilities are highly energy-intensive and require a high power demand. Using renewable energy systems to meet the high demand is optimum to make health facilities more environmentally friendly. The strict service requirements, regulations, and standards imposed on health facilities are the main reason for their high energy demand. A simple example is the National Fire Protection Association (NFPA) for health facilities’ backup generators which is frequently followed by most hospitals that dictate that backup generators must be activated within 10 seconds (Code, 2009). As a result of such standards, all generator sets must be equipped with water jacket heaters that pre-heat the engines for faster start-up time. These water jacket heaters run continuously and have high power demand; a solar photovoltaic (PV) system would be suitable to supply a portion of this power demand. Similarly, the collector and photovoltaic solar systems can supply a significant portion of the healthcare engineering services load demand.

Many studies either investigate or design existing thermal solar collectors or photovoltaic systems installed in hospitals. For example, in their research, Tsoutsos et al. (Tsoutsos et al., 2010) examine the solar fraction of a solar cooling system installed in a Greek hospital. They found that the solar fraction cooling and heating for the established solar collectors’ system size can reach as high as 74% and 71%, respectively. Lima et al. (Lima et al., 2015) use simulation to study the technical and financial viability of a water solar collecting system for a hospital laundry in Brazil. Lima found that the solar heating system could result in 6.3% of the initial cost, making the system more green and cost-effective. Meanwhile, in a Cyprus hospital, Kassem’s et al. (Kassem et al., 2021) research objective was to evaluate the potential of photovoltaic solar power. Their research found that annual electricity generated from the proposed photovoltaic system varied between 2.63 GW and 2.85 GW. In addition to the economic and environmental benefits of installing solar energy systems in hospitals, a significant improvement in resilience is added. In their research, Lagrange et al. (Lagrange et al., 2020) attempt to quantify the benefits provided by an improvement of energy resilience after adding renewable energy sources to a hospital. Their results show a possibility to increase resilience in power outages and an overall savings of approximately $440,000 over 20 years of lifetime. According to the International Energy Agency, the healthcare sector contributes approximately 5% (2 billion tons) of global CO2 emissions, while the energy, transportation, industry, and residential/commercial sectors contribute higher percentages, with energy at 70%, transportation at 15%, industry at 10%, and residential/commercial at 8%. In his study, Vourdoubas et al. (Vourdoubas, 2019) demonstrate the high energy consumption of a hospital in Greece to be around 280 kWh m² per year and the CO₂ emissions due to operation to be approximately 168 kg CO₂ m² per year. He also estimated the cost required for different combinations of solar thermal energy, solid biomass, and solar-PV energy to supply the hospital’s energy demand and provide that it would be profitable to replace conventional energy sources. Meanwhile, in Iraq, in their study Ali (Ali, 2021) designed a PV system for a hospital in Mosul city. In a country where power security is poor and routine blackouts occur, power through PV panels would enhance the resilience of the hospital and reduce the dependency on backup generation.

Chau’s (Chau et al., 2018) case study focuses on the cost and solar efficiency daily operation of a New Jersey hospital’s microgrid containing PV and energy storage systems. Their results encourage investing more in energy storage systems to capitalize on the excess energy generated from the system and store it for later use. However, Chau’s conclusion is only applicable to their case study, particularly hospital location, as the economic viability of the PV and energy storage systems is directly affected by several regional factors such as weather, gross domestic product (GDP), policies, and so on. Examples of support policies for rooftop PV include net metering, feed-in tariffs, tax incentives, and rebates. Alrawi’s results (Alrawi et al., 2022) in Qatar further elaborated on the discrepancy in results. He provides that energy storage systems are not yet economically viable in his region under their current conditions. This revelation opens up new opportunities for research on solar systems case studies depending on their regions. Ghaleb et al. (Ghaleb and Asif, 2022) examine the feasibility of utilizing solar PV systems on commercial building rooftops, identifying physical hurdles and calculating roof utilization factors and PV utilizable area using remote sensing techniques and site visits. The study found that commercial building rooftops have low usability for solar PV due to 16 different types of physical hurdles, leading to roof utilization factors ranging from 0.45 to 0.52, depending on the orientation of the building. The PV utilizable area at the city level was also calculated using regression analysis. At the same time, Soto et al. (Soto et al., 2022) review the challenges and opportunities for implementing solar energy in health centers in developing and underdeveloped countries, particularly in remote or rural areas. The study identifies challenges and opportunities in operational, environmental, and economic impact areas and shares best practices for implementing solar energy in the healthcare sector.

One common theme that most studies on using renewable energy sources in hospitals is increased resilience (Vaziri et al., 2020; Cohen, 2016). For example, Kyriakarakos et al. (Kyriakarakos and Dounis, 2020) discuss the feasibility of renewable energy sources and their capacity to accomplish energy efficiency and on-site power generation. In addition, Liu et al. (Liu et al., 2021) discuss energy storage systems’ role in increasing resilience in healthcare. By calculating economic indicators such as net present cost (NPC) and cost of energy (COE), they could gauge the improvement in a hospital’s microgrid resiliency. Furthermore, Achour et al. (Achour et al., 2014) investigate hospital resilience to natural hazards through the classification and performance of utilities. The six utilities they identified were electricity, gas supply, water supply, landline telecommunication, mobile phone, and Personal Handy-phone System. Achour concluded that hospitals should reduce dependency on these utilities and increase resilience by using alternative sources. Hospitals play a critical role in our societies; they must be robust to run their vital services. Integrating renewable energy systems in hospitals helps increase resiliency and utility security, improve environmental performance, and reduce costs in some cases (Roaf, 2007). In terms of thermo-electrical evaluation of a rooftop PV technology for a residential building, Sohani et al. (Sohani et al., 2023a; Sohani et al., 2023b) study reveals significant annual variations and suggesting the potential for enhanced performance through cooling techniques and concentrating strategies.

There is a noticeable absence of effective solar policies and a consequent lack of widespread solar collectors and PVs implementation in the GCC region. The utilization of renewable energy sources is limited, experimental, and isolated, with only a few government-led projects like solar farms being in operation. The lack of policies has hindered the growth of commercial and residential renewable energy applications. Consequently, there is a scarcity of research in this area, making any studies on this topic highly valuable for the region. A previous study (Alrawi et al., 2022) examines the economic viability of rooftop PV and energy storage systems in Qatar, using three datasets and several economic indicators. The results show that there is a real challenge for PV systems implementation due to the lack of support policies in the region and suggest that Feed in Tariffs and support incentive programs schemes are necessary to encourage the use of PV systems. Still, energy storage systems are unfeasible due to high costs. Cheap electricity prices and energy subsidies also present challenges. Demand-side management techniques and policies that encourage the self-use and selling of surplus power are recommended. In his research, Alghamdi (Alghamdi, 2018) concludes that using PVs to construct a hospital in Dammam is a viable option despite grid power interruptions. The simulated grid-connected PV system provided the most economical solution in all scenarios, with a sellback rate higher than the grid energy price by 5%, yielding the optimum solution. The proposed system reduces all emissions with a minimum percentage of 69.75%, and it results in lower costs compared to the existing system.

Studies that explore the utilization of multiple solar energy sources in conjunction with engineering services in real-world settings, particularly in healthcare facilities in the Gulf Cooperation Council (GCC) region. Most existing research in this field focuses on single-source solar energy and is often limited to simulation-based investigations. The current study aims to bridge this gap by conducting a thermodynamic analysis of a solar photovoltaic system for a GCC hospital that uses two forms of solar energy and is integrated with existing engineering systems. Furthermore, the study employs a unique Solar System evaluation method that draws on the expertise of a technically proficient engineering team. Consequently, this research has the potential to contribute significantly to the understanding of solar energy system design and evaluation in the GCC region and beyond while also providing insights into the technical, economic, and thermodynamic feasibility of integrating such systems in healthcare facilities.

The novelty of the study lies in its investigation of the potential use of solar energy systems in healthcare facilities in the GCC region. This is a unique and previously unexplored area of research, and the study is the first of its kind to examine the impact of multi-solar collector and photovoltaic systems in healthcare facilities in the region. The study also employs a novel Solar System evaluation method involving a realistic and technically proficient engineering team evaluation. Moreover, the thermodynamic analysis and project evaluation conducted in this study are unique and have the potential to benefit all countries in the region that share similar economic and geographical conditions. Therefore, this research has significant implications for healthcare facilities in the GCC region and beyond, as it offers new insights into the potential benefits of solar systems in terms of energy efficiency, cost savings, and environmental sustainability.

The research methodology aims to investigate the potential impact of incorporating multi solar collectors and photovoltaic systems into healthcare facilities. The proposed system will be evaluated using thermodynamic analysis to assess energy and exergy efficiencies, as well as its technical and economic viability. Furthermore, the research will measure the adoption rate of solar systems by healthcare technical departments. The primary objective of this research is to determine the feasibility of using solar energy to reduce energy costs, increase energy security, and promote sustainability in healthcare facilities. Any technical or economic barriers to adoption will also be identified. To complete the project evaluation, experts in facilities management and project engineers will be surveyed.

By creating a combined solar collector and PV system, the proposed system aims to generate renewable energy and reduce the healthcare facility’s reliance on grid power. This will lead to a reduction in energy costs, improved energy efficiency, enhanced sustainability, and increased energy security. By utilizing solar energy to provide heating, cooling, and electricity, the healthcare facility can become more energy-efficient, reduce its carbon footprint, and contribute to a cleaner environment.

The proposed system includes renewable energy sources, engineering systems, and services. The primary sources of the proposed system are collected and photovoltaic solar energy. Although water is another input source, any additional additives, such as chemicals used in chemical dosing systems for water treatment, are not considered. The engineering systems that provide the hospitals’ utilities related to the proposed system are the heat ventilation and air conditioning (HVAC), chillers, domestic water supply system, backup generator sets, central battery system (CBS), and uninterruptable power supply (UPS). In addition, the proposed system supplies chilled water used for air cooling, hot water, and freshwater for domestic use, air, and electricity.

Table 1 demonstrates the operation conditions such as temperature, pressure, mass flow rate, enthalpy, entropy, and exergy of different points in the system, where each point is reflected in Figure 1. The ventilation and water systems have been designed in accordance with international standards such as BSI, ASHRAE, ANSI, ASME, and HTM to supply the hospital with optimum quality services. Therefore, the temperature, mass flow, and pressure parameters are designed to meet these standards. The enthalpy, entropy, and exergy values were calculated using Engineering Equation Solver (EES) software (Software). Table 2 demonstrates the system energy and exergy efficiencies obtained through EES.

The temperature and pressure real values are measured in real-time sensors and can be viewed using a building management system. The mass flow values are based on the building design calculations. The surrounding temperature is assumed to have 22°C, and atmospheric pressure is since the majority of the system is inside air-conditioned plant rooms.

The equations used throughout the study are listed below. However, losses associated with these systems, such as thermal losses due to insulation inefficiencies and air leaks, are not accounted for. In reality, water lost due to evaporation or leaks is compensated through a make-up water supply.

A. Solar Thermal System m 2 . + e x 2 + Q s o l a r , T .   1 − T 0 + 273.15 T s u n = m 1 . .   e x 1 + Q l o s t , T .   . 1 − T 0 + 273.15 T b + 273.15 + E d e s t , T . η e n . T = m 1 . . h 1 − m 2 . . h 2 Q s o l a r , T η e x . T = m 1 . . e x 1 − m 2 . . e x 2 Q s o l a r , T . 1 − T 0 + 273.15 T s u n

B. Solar PV System contribuation to HVAC system load S o l a r S u p p l y = 100 . Q s o l a r , P V C P 1 p + C P 2 p + C P 3 p + C P 4 p + C P 5 p + C P 6 p + W C o m p r e s s o r . + W F a n .

C. Compressor m 1 . . s 1 + C P 1 P = m 2 . . s 2 + Q l o s t , C 1 . m 1 . . e x 1 = m 2 . . e x s + Q l o s t , C 1 . .   1 − T 0 + 273.15 25 + 273.15 + E d e s t , C 1 . η e n . C 1 = m 1 . . h 1 − m 2 . . h 2 C P 1 P η e x . C 1 = m 1 . . e x 1 − m 2 . . e x 2 C P 1 P

D. Heat Exchanger m 1 . . h 1 + m 4 . . h 4 = m 3 . . h 3 + m 2 . . h 2 + Q l o s s , h x 1 . m 1 . . s 1 + m 4 . . s 4 + S g e n , h x 1 . = m 3 . . s 3 + m 2 . . s 2 + Q l o s s , h x 1 . 50 m 1 . . e x 1 + m 4 . . e x 4 = m 3 . . e x 3 + m 2 . . e x 2 + Q l o s s , h x 1 . . [ 1 − T 0 + 273.15 25 + 273.15 ] + E d e s t , h x 1 . η e n . h x 1 = m 3 . . h 3 − m 4 . . h 4 m 1 . . h 1 − m 2 . . h 2 η e x . h x 1 = m 3 . . e x − m 4 . . e x 4 m 1 . . e x 1 − m 2 . . e x 2

E. Economic indicators N P V = ∑ t = 1 n C F ( P V k , n ) − I C

Where CF is cash flows, PV is the present value at k% interest for period n, and IC refers to the initial investment cost. 0 = ∑ n = 0 N C F n 1 + I R R n

Where N is the lifetime of the system.

The results of the EES are depicted in Figure 5. Notable findings are the system contribution of the solar thermal system, which is approximately 12% of the total hot water system energy requirement with 46% efficiency, and the system contribution of the solar PV system, which is around 29.6% of the total HVAC load. The input solar energies of the thermal and PV systems are 180 kW and 400 kW, respectively.

The comparison between the GCC region’s solar thermal and PV systems relies on several factors. The primary factor is the need for the services each system provides; Simultaneously, electricity demand is very high due to the high demand for energy needed for air-conditioning in the region; hot water is a commodity required mainly during winter. However, hot water is necessary for healthcare facilities for multiple applications. The second comparison is related to the system’s complexity. Solar PV requires additional components and storage units; this factor becomes less relevant on a more extensive scale application in healthcare facilities where storage units are already used for power backup systems. The DC voltage supplied by the PV system can be integrated with the existing storage units, reducing cost and maintenance requirements. Both systems enhance the resiliency of the healthcare facility in case of emergencies. In addition, renewable energy further provides environmental and economic benefits.

In conclusion, the results of this study demonstrate the potential of utilizing combined solar thermal and PV systems in healthcare facilities in the GCC region to reduce energy costs, increase energy security, and promote sustainability. However, the exergy efficiency of the solar thermal system needs to be improved to enhance its overall efficiency.

The thermodynamic analysis results demonstrate that the proposed solar thermal system contributes approximately 12% of the hot water system’s energy requirement with 46% efficiency, while the solar PV system contributes around 29.6% of the total HVAC load, highlighting the potential of both systems to enhance energy efficiency and reduce reliance on conventional energy sources in healthcare facilities.

The economic analysis results of the PV system implementation in the GCC region with FIT values of 0.10 ($), 0.13 ($), and 0.16 ($) reveal that the corresponding payback periods are 15 years, 10 years, and 9 years, respectively. These findings demonstrate that higher FIT values are associated with shorter payback periods, indicating a faster return on investment. This highlights the economic viability and potential profitability of implementing PV systems in the GCC region, with the potential for achieving financial goals within a reasonable timeframe.

Based on the feedback from the survey of engineering staff, it is recommended that healthcare facilities in the GCC region consider adopting solar energy systems to achieve their energy goals. Additionally, it is recommended that the system’s design and operation be optimized to increase efficiency and reduce energy loss.

Future research could investigate the use of energy storage systems to increase the system’s reliability and performance during periods of low solar radiation. Additionally, further studies could explore the potential of integrating solar energy systems with other renewable energy sources, such as wind and geothermal, to create hybrid systems that offer more efficient and reliable energy production. Moreover, studying the economic feasibility of implementing renewable energy technologies in healthcare facilities would be helpful in understanding the potential financial benefits of adopting these systems. Future research should address the social aspects of community acceptance and health benefits, organizational considerations including financial implications and operational readiness, as well as policy aspects such as government incentives and regulatory frameworks, in order to comprehensively explore the challenges and opportunities of integrating renewable energy systems in healthcare facilities. Finally, analyzing the environmental impact of the proposed system in terms of reducing greenhouse gas emissions and promoting sustainability could also be a valuable area of future research.