In the early 20th century, warehouses had narrow floor plans or had large spaces with high ceilings. Both of these configurations were favourable for natural ventilation due to proximity of windows for wind-driven natural ventilation or the provision for a warm stratified upper air layer to accumulate and exhaust indoor pollutants in the case of stack-driven natural ventilation.
A typical warehouse has metal cladding-steel frame structure and overheating can easily occur due to solar radiation and stratified space especially in regions with hot and humid climate such as north and south India.
With the increasing momentum of the use of mechanical ventilation, natural ventilation and air conditioning during the second half of the 20th century, existing knowledge on the integration of natural ventilation systems as a design and architecture features had become obsolete. Now, the increasing of expectations and thermal comfort and indoor air quality (IAQ) standards had made designers and warehouse owners to choose the more reliable air ventilation option.
When we talk about air conditioning a warehouse, we don’t just mean warehouses, we mean air conditioning any large space such as workshops, production lines, depots, soft play areas, trampoline parks, storage facilities, racks, packing area etc.
Warehouses represent a vast underestimated opportunity for improved operations, lower operational costs, reduced climate impact and a more sustainable building stock through energy management. Overall, heating, ventilation and air conditioning (HVAC) accounts for roughly 30-40 per cent of total energy cost in a warehouse.
Challenges in Warehouse Airconditioning
As the warehouse has minimal air inlets and the roof of the warehouse is heavily insulated, the presence of heat and high humidity is easily sensed in the warehouse compound. The heat gained from morning to evening is due to radiation on the roof, human activity and machineries.
It is extremely difficult to arrange exhaust fans to ensure that fresh air reaches all locations in the warehouse. Obstructions, such as storage racks, interfere with air flow, and stagnant regions tend to develop in corners of the space.
Best Practices in Warehouse Airconditioning
From the traditional naturally ventilated warehouses of the past, warehouse owners are making changes to the air-conditioning approach and moving to HVAC/TFA system to provide comfort environment to employees to increase productivity. The change is also being driven due to the type of storage that the warehouses are being used for.
A best practice is to vary space conditioning temperatures and ventilation rates in accordance with occupancy patterns, warehouse activities and the needs of the stored goods. Using programmable thermostats with time clocks, setbacks and demand control ventilation to reduce energy requirements of HVAC equipment helps automate the air conditioning system which in turn reduces the staffing needed for O&M as well as operational costs. Installing IoT based thermostats on heaters will allow for monitoring and control of multiple HVAC units that sometimes get left in the heating position even during the summer. Another smart strategy that is finding more favour with designers of warehousing structures is to divide the building into thermal zones with separate controls based on space function.
Conclusion
The key driver for the change in air conditioning approach for warehouses is to improve human comfort in an enclosed warehouse with minimal cost as this improves the productivity of the employees working in the space. The proposed ideas are aimed to enhance human comfort of the workers comfort as the current temperature and humidity that are found inside the majority of warehouse in the country are way below standard comfort level due to minimal air exits in the warehouse. The poor IAQ is physically taxing for the staff to conduct tasks consistently in the warehouse.
The other objective of designers is to develop an energy efficient solution for a warehousing organisation that also enhances the ventilation system. Costs are a key factor in warehouse operations and hence, any change has to consider the Return on Investment (ROI) in addition to the human comfort aspects.
Prashant Yadav,
Real Estate & Workplace Lead, North India
Myntra Jobang Pvt Ltd
