Comfort meets efficiency  

The primary functions of an HVAC system are to maintain good indoor air quality by providing sufficient ventilation and filtration and to offer thermal comfort. The selection and design of an HVAC system impact several high-performance objectives, including water usage and sound levels. Thermal Control Business Update examines the most frequently employed HVAC design options deployed to achieve thermal comfort and optimal indoor air quality in public spaces.

HVAC systems regulate temperature, humidity, and air circulation in public areas. Due to the centralised nature of ventilation and air conditioning units, they typically rely on a single main control unit. These systems consume the major chunk of energy, with centralised systems experiencing higher idle consumption, where each unit can be individually controlled. HVAC systems in large public spaces often struggle to provide adequate oxygen and fresh air, and they frequently fail to maintain the desired temperature in zones with higher-than-normal crowd densities.

The energy efficiency of any building operation consumes significant power. Abdulkader Bengali, COO, of ALP Aeroflex India Pvt Ltd. shares that energy efficiency can be achieved through various factors such as design, orientation, structure, thermal insulation, and using HVAC systems and lighting solutions. These measures are to be precisely carried out while building planning. Identifying and selecting the right solutions helps reduce power consumption.

Ventilation

The American Standards consider ventilation rate in indoor spaces, as it consumes 25 per cent of air conditioning costs and 50 per cent of building post-energy costs. To increase ventilation rates, it is essential to consider energy costs without compromising the indoor environment. People breathe around 1 per cent of the ventilation air in contrast to the supply. Delivering air directly to occupants will make the ventilation process an efficient one. For example, personalised ventilation improves air quality in office spaces by directing air towards or around the occupant. This approach enhances focus and comfort by directly absorbing the air due to proximity, making it particularly beneficial in offices for better air quality. 

Proper ventilation is a major need in tropical and larger regions due to humidity. Proper dehumidification can be a challenging task. Many buildings have components for dehumidification and cooling, making it difficult to ensure humidity supply. A separate system is needed for humidification. Humid air can enter the building, leading to mould, smell, and structural issues in large regions without a separate system. 

Adaptive cooling

The building must be addressed while developing an air conditioning system based on the ASHRAE-advocated Standard 55, which is adaptive cooling. Vinod Ramnani, General Manager of A.T.E. Enterprises Pvt. Ltd. (HMX), adds that adaptive cooling encompasses temperature, humidity, air purity and movement. Adaptive cooling considers the activity and clothing of occupants, ensuring comfort regardless of the temperature. Countries like Japan and China are implementing this approach while raising their set air conditioner points from 22 to 28 degrees in public spaces. They encourage people to make changes based on their activity level and clothing type, leading to significant energy savings and reduced carbon footprint.

The traditional view of air conditioning set at 22 or 23 degrees is optimal but needs to change. Incorporating fresh air into the workplace for occupants is requisite and this change in work culture is already being implemented. It is expected to become a common practice for MEPs and HVAC designers.

Insulation

Insulation materials come in open, semi-closed, and closed cells. With extensive experience in insulation, Bengali believes that suitable insulation material is important for technological advancements. Insulation contributes only 3-5 percent of the HVAC system, yet it is a significant and cost-effective energy efficiency measure. Proper installation is required for pipes, as gaps in pipes can cause condensation. Insulation pipes are covered with jacketing like aluminium or GI cladding. When cladding is removed, a self-tapping screw is punctured in the cladding, allowing moisture to pass through, known as thermal bridging. This process of insulation allows moisture to pass through while promoting thermal bridging.

Stakeholders, end customers, designers, and installers, rely on leaders who lead by example. They seek proof of concept and believe in certain elements, leading others to follow. For instance, in the HVAC industry, duct insulation was predominantly done with glass wool insulation, which was the lowest price level. Today, the market has shifted to nitrile rubber base insulation, which is expensive but offers value. This shift is a result of the leadership of individuals and stakeholders seeking proof of concept and moving forward.

The value of a product across all aspects is crucial as is its demonstration across various sectors. For example, nitrile rubber is essential in areas like Mumbai, while EPDM (Ethylene Propylene Diene Monome) insulation is recognised for its long-term performance in government buildings. However, there is still a gap between product value and financial justification. Understanding this gap leads to acceptance and a movement across innovation and every category, with the end customer’s understanding being the most important part.

The wide selection of elements is often overlooked, focusing only on aluminium. Material selection is important in public spaces, as every material has its positive aspects and negatives. For instance, EPDM is used to ensure the safety of public spaces during fires. However, the time available for people to exit and find a path in dense smoke can be difficult, potentially leading to fatalities. Careful selection of materials prevents potential hazards and safeguards people in public spaces.

As Aboulhod adds, “Insulation should align with the operation of the building, such as inside the centre, the inner side, or on the outer/exterior side of the wall. The difference in thermal mass between the building and its interior should be considered. Greater thermal mass takes longer to cool down, while less thermal mass inside the building takes less time. For example, if an area frequently needs quick cooling, insulation should be applied on the inner side of the wall to reduce thermal mass. Integrated installation implementation with operation can lead to more sustainable and energy-efficient solutions using the same insulation.”

Solar

Solar energy is critical for reducing cooling loads and generating electricity. Implementing shading effects on buildings serves aesthetic purposes, reduces cooling costs and generates power. This approach optimises energy generation and efficiency simultaneously.

Solar panels designed in Western countries, where cooling loads are less and outdoor temperatures are lower, are inefficient. Efficiency is reduced when temperatures rise, especially when sunlight is present. To optimise solar panel efficiency, it is suggested to divert return or exhaust air, particularly from toilets or other buildings . This will exchange heat with the panels, reducing energy consumption and making them more energy-efficient when needed. These strategies will maximise the benefits of solar panels during their implementation.

Data analytics and sensors

The data collected from the building shows that the automation system regulates air conditioning, cooling, and heating equipment, with cooler climates requiring heating and tropical climates requiring cooling. This information creates an understanding of the optimal usage of systems. A smart system that responds quickly to building changes is beneficial and it allows operators to make the system smarter. For example, a building with three chillers may benefit from one running at full load instead of three at part load. The same applies to pumps and cooling towers. Data collection makes the system smarter.

Technology

Controls, innovations, and technology provide added thermal comfort for every individual in the building. A paradigm shift is needed in this industry, similar to the telecommunications industry’s shift from black boxes to unique phones catering to individual demands. This approach should be adapted so that individuals are comfortable in the building.

The set-point for a thermostat should be 22–24 degrees Celsius, which can be improved to reduce energy consumption. Thermostats adjust the temperature, but the problem lies in the humidity, which needs to be monitored rather than the temperature. New frameworks are needed for meetings, addressing infrastructure, equipment, and components, dividing space into smaller, comfortable zones, and ensuring each area meets individual needs while remaining open.

Budget Expectations

Bengali believes that every user and developer must understand that they will reap benefits if they build an energy-efficient building. Tenants would prefer lower costs in the long run, which would also create a premise for developers to charge premium rents. It is more of an individual perspective. There is a commercial value in making a building energy-efficient or green.

The Bureau of Energy Efficiency has developed the ECBC (Energy Conservation Building Code), which guides individuals, corporations, developers, architects, and consultants in designing buildings more energy-efficiently. While government initiatives are in place, the commercial benefits of green or energy-efficient buildings are significant.

The Indian government presented the India Cooling Action Plan in 2019, which predicts a 400 per cent increase in air conditioning demand by 2037 compared to 2019 while reducing energy usage by 30 per cent. This plan shall meet the growing population’s need for better comfort in homes and workspaces. Ramnani shares, “The heat wave and global warming have increased energy demands in India. Controlling energy usage and spending is crucial for India, and government policies are in place to address this issue. India is committed to achieving zero carbon emissions by 2070 as part of its long-term plan, and the upcoming budget is expected to have allocations for this commitment.”

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Azmi S. Aboulhod, CEO, EMergy

“Personalised ventilation and targeted insulation can improve comfort and energy efficiency in public spaces. HVAC systems can be optimised to meet individual needs while reducing costs and improving air quality.”

Vinod Ramnani, General Manager A.T.E. Enterprises Pvt. Ltd. (HMX), 

“Adaptive cooling comforts by integrating temperature, humidity, and air quality based on occupant’s activity. It also reduces energy use and advances sustainability in global building practices.”

Abdulkader Bengali, COO, ALP Aeroflex India Pvt Ltd.

“Proper insulation in HVAC systems with materials like nitrile rubber and EPDM ensures energy efficiency and safety in public spaces, ultimately benefiting developers and tenants.”

Mihir N. Patel, Consulting Engineer, HVAC. 

The thermal comfort market is focusing on sustainable technologies to reduce energy use and decarbonise, moving away from non-renewable and environmentally harmful sources.

Manish A Dandekar, Proprietor, HVACR Systems

Achieving energy efficiency in large spaces involves advanced HVAC systems that adjust heating and cooling based on real-time occupancy and weather conditions.