Supermarkets are designed to make the shopping experience better compared to traditional retail stores. Today people visit supermarkets (and malls) to buy food, goods and services, or simply to go window shopping in a comfortable environment. Supermarkets can be thought of as closed environments that not only offer products, but that in many cases also stimulate us to purchase them. Indeed, people buy products either when they need them or when they are enticed to do so.

The former case seems quite straightforward at first: a person simply enters the supermarket, buys the products they need and leaves. Naturally, however, the supermarket has to present the products in a way that gives shoppers confidence in their apparent quality, otherwise they wouldn’t spend their money. Additionally, the supermarket needs to offer an acceptable level of comfort to create shopper loyalty, otherwise they may change stores.

The latter case, i.e. tempting people to buy products regardless of whether they really need them, exploits the emotional side of humans, as anything that gives us satisfaction makes us feel better. Consequently, in CAREL HVAC/R Corporate Business Manager Raul Simonetti’s opinion, the supermarket’s internal environment must be designed to make people feel so comfortable and relaxed that they focus their minds on the goods displayed, temporarily forgetting other thoughts, so that some of the products become the exact objects that can give them that much sought-after, and induced, satisfaction and happiness.

He says, both situations require architectural solutions that can be summarised as: proper lighting, low noise, comfortable indoor air quality (IAQ), spaces for merchandising the products, spaces for resting (food courts, cafes and so on), spaces for leisure (for instance, where kids can play, with or without supervision), bathrooms, ample parking, etc.

Focusing on IAQ in particular, this represents the best temperature and humidity values and the lowest concentration of pollutants (CO2, VOCs, dust, others) that are suitable for both human comfort and the correct preservation of food, where this is displayed.

Even in India, a host of leading supermarkets are offering the best deals on food, fashion and accessories, home appliances, groceries etc. However, being complex buildings, these supermarkets face tremendous challenges especially with regard to heating and ventilation that can affect the IAQ.

“Supermarkets are prone to high indoor air pollution because of the hindrance to proper ventilation and increase in humidity, especially during peak hours, and thus the impact on customers increases with increase in number of customers,” says Udayan Banerjee, Head of Operations and Founding Member, Clairco – a Bengaluru-based clean air start-up.

According to Banerjee, the factors that contaminate air in supermarkets are:

  • Building materials, paints, and floor tiles contains asbestos and formaldehyde which are leading sources of volatile organic compounds (VOCs) and fine particles called Particulate Matter of 2.5 micron (PM2.5). These are one of the most hazardous pollutants and prolonged exposure to these can cause serious respiratory diseases including lung cancer.
  • Pollutants in outside air also contribute significantly to the pollution inside, specially PM2.5, which is generated due to construction activities, vehicular emissions etc.
  • Humidity is another factor which causes high concentrations of these pollutants.

Around the wet areas like pantry deep freezers and AC units, formation of slime is often observed which contributes to production of different kinds of harmful germs and bacteria. These get mixed in the return air of HVAC system and contaminate the indoor air, opines Manish Kumar, Regional Service Manager, Reliance Digital Services (HVAC), Reliance ResQ.

How to maintain indoor air quality in supermarkets

Talking about how to maintain IAQ in supermarkets, CAREL’s Raul Simonetti explains, since supermarkets and shopping malls are closed environments, the indoor air needs to be regularly changed, introducing outdoor air
and removing the “used” indoor air, in order to:

  • Control the indoor temperature and humidity, at roughly 17-25-degree C or 63-77-degree F and 30-50 per cent rh (winter-summer).
  • Control the concentration of pollutants: these are produced both by people (CO2, VOCs, dust from clothes and brought in from the outside) and by the various activities taking place inside the premises, such as moving goods, baking bread, and so on.
  • Abate the heat gains from the sun, the lighting and internal processes (e.g., cooking in food courts).

The supply air is often a mix between outdoor air and recirculated air, the latter being reused to save energy, as it is already close to the desired indoor conditions. In Raul Simonetti’s opinion, both the outdoor air and the recirculated air need to be filtered and conditioned by heating or cooling, humidification or dehumidification before being delivered into the supermarket in order to accomplish the three tasks listed above.

“The exhaust air can be partly recirculated and partly discharged, depending on where it is extracted from – it may be filtered to remove particulates and pollutants that cannot be recirculated (such as airborne grease particles from kitchens) or it can be fully expelled being unsuitable for recirculation,” he adds. “In general, however, recirculation is the easiest way to achieve energy saving; as regards the air being expelled, it is useful to have it pass through an energy-recovery system (for example, a cross-flow heat exchanger or equivalent) so as to recoup as much energy as possible, before it is sent back outside.”

Raul Simonetti also suggests: “Dedicated sensors can be used to measure temperature, humidity, CO2 (more commonly), some VOCs (not so common): their readings are collected by controllers or supervisory systems to decide, based on the algorithms implemented, how to manage the ventilation system/systems serving the shopping centre and thus guarantee the optimum indoor conditions while minimising energy and water usage (note that water is an efficient cooling medium exploited by evaporative coolers).”

As per Manish Kumar of Reliance ResQ, the basic of disinfecting the contaminated air is to remove or kill the harmful germs or bacteria. It is known that the majority of air supplied to any space is returned to the AHU for reconditioning or exhausted from the building. This return air may be conveyed in a return air duct system or through plenums formed by various elements of a building. An induct device can be placed to in the plenum to maintain IAQ.

Most supermarkets are air-conditioned. To maintain clean air at all times, air filtration capabilities need to be added to the air-handling units (AHUs) or ACs as well as the fresh air ducts. Additionally, it is very critical to monitor air quality data (PM2.5, PM10 etc) in real time so that the air filters can be cleaned and replaced before the air quality degrades below acceptable levels.

However, according to Banerjee of Clairco, the challenge has always been high capital expenditure involved in adding high quality filters to AHUs or ACs and a lack of data driven approach to managing air quality.

Clairco has addressed this problem through low drag air filters which can be retro-fitted to existing AHUs without affecting the performance of ACs. They also have an IoT-based Air Quality Monitor which enables to monitor the real time air quality data and display it on any connected screen. Additionally, Clairco has a patent pending technology through which it is possible to predict when the filter needs to be replaced thus maintaining clean air at all times, thus guaranteeing clean air.

Clairco provides all this in a much affordable monthly-subscription based model which makes them 3-5 times more affordable than the existing industry solutions, claims Banerjee.

Solutions

Supermarkets, especially larger ones, and malls rely more and more on the best indoor environmental conditions to attract visitors and boost the sales of correctly displayed and preserved products. As per Raul Simonetti, among the equipment installed in shopping centres, modulating ventilation systems play an important role in maintaining the required indoor conditions (main goal) while reducing the energy and water consumption (secondary goal), through the use of modulating components (pumps, heating and cooling devices) and real-time proactive monitoring systems, designed to adapt the components’ outputs to current indoor requirements.