Study on the Optimized Energy Consumption Indicators of the Cooling Systems in One of the Hospital Buildings in Oman

The majority of the world’s energy consumption is attributed to fossil fuels, which in turn release environmental polluting gases such as CO₂, NO₂, greenhouse gases (GHGs), etc. These gases are the root causes of global warming, and throughout the world, scientists, engineers, and political leaders have been working for many years to address the climate crisis. Since 2013, Berkeley Earth, a nonprofit research organization in California, has been working on its own analyses of global mean temperature change parallel to the work of the IPCC. Their conclusion is that the year 2023 was the warmest ever recorded on earth since 1850, and it was considerably and unquestioningly warmer than that in 2016 [1]. Scientific evidence that exists today is not only adequate to prove that global warming is accelerating but also makes the world aware of the fact that planet earth, by increasing its temperature beyond 2℃, will reach an irreversible tipping point and hence be prone to inevitable devastation. Some of the life-threatening impacts of global warming/increase in Earth temperatures are the melting of polar ice, which makes sea levels rise and flood much of the world; more floods and droughts; loss of biological diversity; shortage of food and water, etc. Global warming and other devastating effects of poverty and environmental degradation augment one another or work together in the world, and they threaten the world's societies with far-reaching consequences. Human beings should cut down emissions in a bid to preserve the planet to be inhabited in future habitation [2].

The building sector consumes a substantial part of the energy. Building energy is measured in Energy Performance Index (EPI), i.e., kWh/m²/year. The building’s biggest single point of consumption is HVAC. Heat is a silent killer. It is hard to say when it becomes lethal and how it should have happened, particularly in warm countries like Oman, where high temperatures are considered a natural occurrence. Buildings in Oman consume an estimated 76-83% of electricity, compared to a global average of 40%, with cooling systems accounting for a substantial portion of this energy use [3]. HVAC is the largest contribution to EPI in any building. In most buildings, chillers or unitary types of air conditioners do the cooling. Global energy demand for cooling is expected to triple in the coming decades, according to the International Energy Agency. This increase would further stress electricity grids and release more GHGs. As the planet gets warmer, demand for cooling goes up. In addition, as populations continue to grow, more air conditioners are installed [3].

Throughout the world, scientists, researchers, engineers, and politicians are working to address the major climate issue to protect the planet from disaster. The Paris Climate Agreements, 2015, made a bold (and needed) commitment to limit global warming to 1.5 degrees Celsius above pre-industrial levels. Various renowned institutions have been working for many years to reduce GHG emissions through international protocols. During its last initiative in a recent attempt of the United Nations Environmental Program (UNEP) that was presented at COP 28, some 70-80 world governments signed the Global Cooling Pledge that will tackle the issue of cooling technologies, including the problems. A growing list of countries has signed the pledge and committed to taking immediate steps to improve the sustainability of cooling systems [4, 5].

It is an indisputable fact that energy consumed by the building cooling sector contributes significantly to energy and GHG emissions consumption, which in turn makes energy efficiency in cooling systems irreplaceable, particularly in light of global action to tackle climate change, sustainable development, and resource utilization. The resultant effect is that the energy efficiency improvement process in these systems can offer a lot of economic, environmental, and social benefits. The energy efficiency of a cooling system is highly important in addressing the global problems of sustainability, particularly in a hot world like that of the Sultanate of Oman. Energy consumed, operating costs, and consumption of GHGs are aggravated by the use of traditional methods of air conditioning (AC). The commitment by Oman to the Paris Agreement to reduce global warming and ensure it does not rise above 1.5℃ brings to the fore the importance of the optimization of energy consumption to attain national and global sustainability objectives in cooling systems (United Nations, 2016). Although technological progress has continued to be developed, there is a major shortcoming in measuring procedural examination and the establishment of energy-efficient cooling frameworks across different types of buildings in Oman [6, 7].

The magnitude of the challenge is demonstrated by preliminary research developed in a hospital complex with a total AC plant capacity of 300 TR. The complex consumed 2,257,190 kWh in November 2023 alone, proving the principle of innovative interventions that can be optimized in the area of energy consumption. Through comparison of performance according to the important measures, such as the Coefficient of Performance (COP), Energy Efficiency Ratio (EER), and Seasonal Energy Efficiency Ratio (SEER), this paper found the means of achieving significant efficiency improvement. These findings provide, however, only an initial entry point. It should be extended to other forms of buildings, such as prayer halls, office blocks, and sports facilities, so that a comprehensive theory of energy-efficient cooling systems could be developed in Oman [8, 9].

What is common among the existing works is a focus on general energy efficiency measures, whereas little attention is given to such a unique problem as the cooling systems of hot climates. To illustrate, although the incorporation of smart chillers and alternative refrigerants that meet the F-gas directives appears to be a potentially viable option, there is still a lack of practical application of these in Oman. Moreover, potential solutions for reducing dependence on fossil fuels through the addition of renewable energy sources (e.g., solar-assisted cooling) still need exploration on their techno-economic viability. The solution to such gaps requires a multidisciplinary intervention integrating high-level energy audits, innovative technologies, and economic assessment based on the particular environment and operation conditions in Oman [10-12].

By filling this gap conceptualized in this research, the proposed work will maximize the practical benefit of theoretical progress through the development of a unified framework to gain energy efficiency in cooling systems in buildings of different types in Oman. Using the data of the various case studies used in the study, e.g., the hospital complex and the promise of future studies on more building categories, the study will present effective and new approaches towards minimizing energy use and the GHG outputs, and yet make it affordable. The results will also support energy efficiency in Oman, as well as offer an easily replicable pattern in any other GCC country that is struggling with such issues. This study is ultimately harmonious with the global initiative toward incorporating sustainable urban development into the ways of achieving climate change and energy efficiency [13-15].

The current research fulfills a critical research and application gap in energy efficiency of cooling systems in Oman, as it is the first to test and provide an evaluation of real-time operation optimization in Oman, namely reversing the direction of chilled water flow, using experimental data across a period of one year. In contrast to the theoretical or simulation-based studies of the past, this study proposes some measurable energy savings, CO₂ reduction, and OPEX relief using live chiller data. It presents a techno-economic platform aided by machine learning designs (MLP-ANN and Random Forest), IoT-assisted tactics, and SEER/COP benchmarking. Above all, it provides a foundation for a scalable approach to other types of Omani buildings, such as prayer halls, office blocks, and sports complexes; thus, it can not only be viewed as a technical contribution but also a policy-facilitating model to the Omani Vision 2040 and Paris Agreement commitments on sustainability [16-18].

The growing demand for energy-efficient cooling systems, particularly in regions with hot climates, has prompted extensive research into innovative solutions for optimizing energy consumption in buildings. Brambilla et al. [1] reported a case study on an environmentally efficient energy retrofitting methodology. The case relies on the methodology developed by them. In this paper, the authors demonstrated a case study of high-energy-efficiency building renovation and the integrated design process methodology used to improve the building's environmental performance. The authors found that the practiced methodology could be mentioned as an excellent solution to low-energy retrofits close to nearly zero-energy buildings, along with a paradigm of a smart and environmentally friendly reuse of an existing construction, targeting the environmental efficiency maximization of the building from cradle to grave. Studies by Al-Saadi et al. [7] emphasized the significant potential of LED lighting and solar control films to reduce cooling energy requirements across diverse facilities in Oman, achieving savings of over 60% in various building types. These findings validate the importance of integrating passive and active energy-saving measures, particularly in large-scale facilities like hospitals and sports complexes. To that end, Alalouch et al. [5] looked into energy-efficient design actions and building specifications and estimated energy savings between 13 and 48 percent by 2040 in the Oman residential market. The fact that such studies imply the necessity of a systemic approach to implementation of the technological upgrades, along with the consideration of the ideas of sustainable design that should be used in the Oman context to meet the growing energy needs. HVAC systems, as dominant energy consumers in buildings, have been a focal point for energy efficiency research. Such a percentage is 65-70 of all the energy consumption in the Omani hospital HVAC systems [8]. Operation of the chillers can be optimized, and the settings of the air-handling units can be adjusted to reduce monthly energy consumption by 15 percent, proving the physical value of changing operations. Katipamula and Brambley [23] also pointed out that consistent HVAC maintenance helps parties avoid overconsumption of energy by as much as 27.5%. This is in line with Mohseni-Gharyehsafa et al. [24], who proposed that sustainable HVAC designs should have a smart system and water recovery, which aims to obtain energy efficiency in the long term. This evidence confirms the initial results of the current study that can save significant energy depending on the changes made in the ways of system operations, like changing the directions of water flow in chillers.

Digital technologies have grown to the point of optimizing building energy performance with further benefits. Dulce-Chamorro and Martinez-de-Pison [3] developed their predictive modeling combined with the Building Management Systems (BMS) to optimize energy consumption and improve performance in Spain to 7-10 percent energy savings and 82.7 percent improvement. Just the same, Bamdad et al. [25] discussed how the Internet of Things (IoT) could achieve a balance between energy efficiency with better indoor air quality (IAQ) using machine learning and recalibrating sensors. The technologies are promising to help in dealing with inefficiencies in Oman cooling systems, especially when coupled with power energy sources through means like solar energy, as suggested by Alalouch et al. [5]. The latter laid focus on the contribution to the solar photovoltaic (PV) projects, whereby, in GCC, it is projected that it shall compose renewable energy capacity by way of 94 percent by the year 2030.

The merging of renewable energy technologies and matching with energy recovery technologies in HVAC has also been a much-researched topic. Nassif [26] projected that the effectiveness of exhaust air heat recovery, absorption chillers powered by solar energy, and eco-friendly technologies in integration with air-conditioning energy use in office buildings would be reduced by 10-17 percent. Li et al. [27] also backed this assertion with the fact that heat recovery ventilation (HRV) and energy recovery ventilation (ERV) systems had the potential to save energy consumption in net-zero energy buildings by 7.5 percent and 9.7 percent, respectively. These results support the aims of this study to examine renewable energy options and innovative technologies for optimizing cooling systems' performance in Oman. Al-Saadi et al. [7] also attached importance to the energy auditing value, and it has been found that it is possible to decrease the level of energy use in government buildings by 38.5 percent in Oman, which shows that the importance of regularized assessments of inefficiencies cannot be overstated.

Combined together, the themes that these studies may tap into are the impending multifaceted insights into the energy efficiency maximization in the cooling system. Although immense progress has been made to determine measures of saving of energy saving, there still remains a lot that is not known or understood as far as answering the question of how/if some of these measures are viable in the techno-economics they find application in Oman with its various climatic and operational conditions. The given study comes up with these revelations and targets different building types, changes in operation, and the adaptation of innovative technologies to create a scalable model of sustainable cooling. Although this strategy may seem to be in line with the global agenda of mitigating GHG emissions, Oman has its local energy problems, and this strategy supports the sustainability agenda pursued by the country.

Table 1 is a summary of different and advanced research on energy efficiency practices that are available, and that pay attention to HVAC systems and cooling technology in numerous settings, and there is a profound interest in the application of the same to the unique climatic and working aspects in Oman. Literature indicates breakthrough interventions like LED lighting and solar control films that can save lots of energy in Gulf countries' education and sport-related facilities, as well as approaches to integrate solar PV technologies that are in line with future GCC renewable energy objectives [5]. IoT-powered systems such as IoT-enhanced IAQ systems [25] or predictive tidying of BMS [3] are advanced methodologies through which smart technologies have become paramount to the micro-optimization of energy use. Intervention potential can also be addressed with reference to Oman, where it was noted that modifying the work of hospitals HVAC systems in order to reduce energy consumption by 15 percent [8]. The role of maintenance routines [24], energy-efficient design interventions [5], and energy recovery technologies [26] is also mentioned as vital to long-term sustainability. Not only does this extensive review confirm the importance of special cooling system refinements that are strongly required, but it also combines the innovations on a worldwide stage, providing a well-built base on which efficiency plans can be improved in the energy sector of Oman in the context of building.

Table 1. Combining international novelty and domestic expertise: A synthesis of the efficiency of HVAC systems and cooling technologies in Oman

Recent research has indicated that it is high time to streamline the HVAC systems in the hot conditions in Oman by implementing operational strategies and interventions based on auditing. As an example, Al-Badi and Al-Saadi [21] highlighted the passive and active cooling adaptation of Omani buildings, whereas Guangul and Kandothillath [22] have shown the realization of energy savings valued by low-cost HVAC auditing in the institutions. These articles confirm the usefulness of on-site, site-specific HVAC enhancements and provide a methodological basis for the study.

The study considered factors such as variable flow implementation, chilled water temperature adjustment without affecting the quality of services, flow rate optimization, environmentally friendly refrigerants, and using efficient motors, etc., for chillers in a hospital complex in Oman based on data collected from a certain period. Some of the aspects and their details are shown in Table 3.

Table 3. Some aspects and their details are considered for the study

An additional study will be carried out to identify potential cost reductions and operational improvements. This research will give decision-makers significant insights into optimizing chiller performance and improving overall hospital efficiency. By identifying areas for improvement, the hospital may be able to minimize energy expenditures while also improving its sustainability.

Table 4 shows the technical description of chillers in Oman's hospital complex, including model numbers, cooling capacities, and energy efficiency ratings. 12 no’s of air-cooled chillers with screw-type compressors generate chilled water to serve the various AC systems of the hospital. Three chillers are under emergency circuit to serve the critical areas such as the operating theater and ICU, etc. This hospital is approximately a 900-bed hospital. Each chiller machine is provided with an associated primary pump. In addition, two numbers of secondary chilled water circuits are provided, one to serve the AHUs associated with essential departments, the other serving the remaining AHUs. From the main chilled water pump house, the chilled water flow and return pipework will run via a main services route to the buildings, where it will run along the services streets to serve the various plant rooms. Chilled water pipework is fully insulated and vapor sealed. The AHUs are housed in plant rooms located around the building, each plant room serving the departments local to it.

Table 4. Technical description of chillers in a hospital complex in Oman

The first phase of the research included an experimental design, in which the direction of water flow into and out of 12 chillers in a hospital complex was altered between November 2023 and October 2024. The objective of this experiment is to assess how changes in water flow impact energy consumption and overall efficiency of the chiller systems, i.e., the use of variable flow instead of conventional constant flow. The initial outputs of this experimental stage were to evaluate what can be done to save time on energy, and such outputs will later be extended to other buildings, such as prayer halls, office buildings, and sports complexes in Oman, to streamline cooling systems within different building designs. This experimental design helped to establish a direct relationship between operational adjustments and energy savings, providing critical insights into optimizing HVAC system performance.

In parallel with the experimental design, a comprehensive data collection process is being carried out. This process involves collecting energy consumption data over a minimum of two years from selected buildings (one of the buildings is a hospital), along with relevant design, operation, and maintenance (O&M) details. The information is either directly taken using the current records or the live monitoring systems, where possible. The cumulative information will be related to the energy consumption pattern and application, cooling system performance, and ongoing maintenance to form an analysis base for the energy study. The study shall be conducted in accordance with international norms in an effort to determine the inefficiencies and what could be done about them, i.e., their inorganic nature, poor system interaction, or high utilization of energy, COP, SEER, etc. This paper will identify possible new ways in which this can be achieved politically, technologically, or managerially. Measurements to control them will subsequently be introduced because of the research results, and the impact of the measures on the quality of energy consumption and cooling services will be registered and analyzed.

The energy consumption data that will be collected will be analyzed using Python software and some appropriate statistical tools (SAT). Suitably, after the research is conducted, the data collection format is prepared according to the international standards. In the analysis of the data, the analysis of time series analysis, regression modeling, and performance simulation will be used to determine the trend and patterns of energy consumed in each of the building types. This analysis shall be used to benchmark the cooling system's performance with the acknowledged international Product Energy Performance indicators (EPI), including LEED/Energy Star. These results will then be translated into a techno-economic assessment, determining the cost-effectiveness of the different measures/strategies to reduce energy, as well as control strategies. Defining the probability of implementing these measures at a larger scale within Oman's building sector using techno-economic analysis will make the entire exercise a comprehensive way to ensure that energy efficiency is achieved, as well as minimize its impact on the environment.

In addition to hospitals, optimized cooling systems suggested in this paper, including the adjustment of water flow, the temperature of chilled water, and the monitoring of the performance with the help of IoT, are applicable to mosques. Which are not used all the time, but those where the cooling volume needs to be very high with a significant number of users during the high load periods, particularly the Friday prayers. In the same way, office buildings have daily and seasonal variations in loads that can be considered optimally controlled with adaptive controls and variable flow systems that can achieve great results in terms of reduction of base-load energy consumption. Unpredictable but high cooling loads of sports complexes could be used to take advantage of predictive modeling and ensure that the chiller is turned off when the building is vacant. These cases support the scalability of our solutions to various building typologies in the hot environment in Oman.