Hvac Systems

The workplace dynamics have changed dramatically, post-March 2020, with the announcement of the Lock-down in the country and subsequent events that unfolded. We are not the only witness to this change but are impacted by the changes that are occurring around us. COVID-19 has radically altered many aspects of our lives that we took for granted – social interactions, working in offices, going out to the mall for a shopping binge, the dinner date and many other activities that we are no longer undertaking. Hopefully, this is a transition phase and will be behind us shortly and we will get back to life as it was.

Till we do, HVAC systems in buildings, industry, hospitals, homes etc., will have to be managed according to new norms as people will still need to work and be productive. There will however be a need to operate the system differently for the HVAC to be effective as well as optimal. How the O&M teams and engineering managers will need to adopt is the subject of this article – goes without saying that as the environment changes rapidly around us, the approach that the HVAC industry takes will continue to evolve.

What has changed for the HVAC Industry!

Many things; and at the same time, not much! HAVC systems still need to be operated and the operators need to run the plants in the same manner as before – see that the water and gas parameters are as per the design requirements, temperatures have to be maintained and the maintenance of the system has to be undertaken. What the O&M team did before March 2020, needs still to be done as the HVAC system has not changed, or at least most of it has not.

What has changed, is the way the systems are now operated. A central chiller designed for a building occupancy of 80% on a given day with a certain heat load to be managed is now required to operate and service a building where the occupancy has come down to 10% or even less in some cases or at some points in time. This significant change from the building design point will
impact the chiller operations in many ways and will need an altered approach to O&M. With the chillers not operating as they should, will there be a need to alter the maintenance schedules, the preventive maintenance plans etc., are questions that engineering managers are grappling with.

A major change that has occurred is the shortage of O&M staff, mainly at the plant operator and maintenance team level. Some have migrated their hometowns; some are unable to reach their workplaces, so the availability of trained and experienced HVAC personnel has become a challenge for a country with a billion plus population.

Managing HVAC Systems in the Changed Environment 

While the basics of O&M will continue to remain the same such as operating as per the OEM/manufactures guidelines, safety, hygiene, etc., there will be a need for major and minor adjustments.

Revised Industry Standards/Guideline: Changes in operating conditions always bring in changes to the way systems are operated and this is no different for the HVAC industry. Industry bodies, government agencies and manufacturers have responded to the changing environment and taken out guidelines and in some cases directives on HVAC related aspects. Since the industry is mature and professional one, the guidance that O&M teams as well as manufactures, consultants, contractors and other stakeholders take comes from trade bodies such as ISHRAE (Indian Society of Heating, Refrigeration & Air Conditioning Engineers) and ASHRAE (American Society of Heating, Refrigeration & Air Conditioning Engineers).

In India, ISHRAE has released guidelines for sector during April 2020 that addresses various aspects of this sector. These guidelines bear out general aspects of the current situation concerning the HVAC sector as well as specific guidance on changes to be made in operations as well as maintenance of the HVAC systems in different work environments. These are excellent well developed and practical documents that industry professionals should familiarize themselves with; to effectively manage their HVAC systems.

Revised O&M practices: With changed circumstances, the way HVAC systems are operated will also need to be modified. Some of the aspects that HVAC O&M teams will have to consider are:

Operational Load: Occupancy in buildings and work-spaces has come significantly down across most sectors and in some essential sectors, there is also a reduction in the number of employees attending work. Work From Home (WFH) is the norm for a majority of work-spaces that utilize HVAC systems for their employee environment. This means that for a building that had an occupancy of 7000 employees on a given weekday, now has only about 500 to 700 attending office and that too in different floors and offices in the building. The chillers in the buildings have not changed and neither have the associated supporting systems – AHU’s, pumping systems, cooling towers, etc. The chillers and associated systems/equipment have been designed for a heat load catering to about 80% to 90% occupancy and now have to cater to a much lower occupancy level. Modern chillers operate at their highest efficiency at a loading of 70% to 80% and in fact, some chiller systems cut out when the loading goes below 25%. Running at lower loads is thus not efficient which leads to higher energy consumption and ultimately to higher operating costs. Thus, in the changing working environment, O&M teams will have to dynamically evaluate the load by constant engagement with the tenants and optimize chillers operations.

Distributed occupancy within work-spaces: Even in the best times, employees complain regularly about hot and cold spots in their offices which is most likely due to improper airflow or distribution. Meeting rooms sometimes tend to get too cold whereas some areas of the office floor just don’t get any cool air. With offices implementing social distancing norms within their work-spaces, the density of staff within the workspace will reduce – where one person on an average occupied 70 to 90 sq. ft., this will now change to 100 to 120 sq. ft., if not more. The AHU systems, ducting and control systems, however, have not been changed leading to further complications in the airflow patterns. Ten-seat meetings rooms henceforth, will now only be allowed for five people, and they will surely get cold. There are no easy solutions to this problem and undertaking any major modifications is not possible at the present, as the situation is changing dynamically. O&M teams will thus have to work with the office administration staff to work out the best possible occupancy patterns that maximize the use of the HVAC systems.

Health Concerns: The occupants of the workspace are genuinely concerned about the health aspects of running AHU’s in the current environment. ISHRAE has in its COVID-19 guidance document on airconditioning and ventilation indicate that by taking simple and basic operations as well as maintenance actions, the HVAC systems are safe to operate in this situation. Maintaining a temperature between 24 to 30 deg C, humidity levels between 40 to 70 degrees, as well as increased fresh air intake are some of the guidelines that are provided to keep the occupants safe. Thus, the O&M teams will need to make themselves familiar with the various industry as well as government guidelines/directives continuously.

Maintenance: A major factor that the O&M teams will have to consider is the way maintenance is undertaken on the various components of the HVAC systems. Changes in AHU filter cleaning schedules, with an increased focus on sanitization and use of recommended chemicals, will be the norm. AHUs are recommended to be kept on during the weekends, so that the work-spaces can be continually ventilated, which means that the equipment will be running more and will need additional maintenance. Another area that the O&M team will have to grapple with is the Annual Maintenance Contract (AMC) – with chillers running for a significantly reduced time, some of the time- based or running hour-based schedules would not fall due as envisioned. There will be a temptation to reduce the scope of the AMC contract or maybe not take it altogether to save operating costs for the current phase. However, this is not advised as the cost of the AMC is a fraction of the cost of the equipment and the overall health of the system. A better approach would be to work with the OEM/AMC service providers to review the operating cycles and arrive
at a mutually agreeable modified AMC plan.


Change is always constant, so the HVAC industry will need to quickly modify the way the air conditioning systems are both operated as well as maintained. This has already begun and with the unlocking of work-spaces and more businesses opening up, there will be more focus on the HVAC O&M teams to deliver safe and efficient work environments for the workforce. The changes are not major and in fact, are an opportunity for the HVAC community to refocus on the basics of design and operations which may have got diluted with time as the fundamentals remain the same and, if followed, the HVAC systems are inherently safe.

Aneesh Kadyan

Aneesh Kadyan,
Executive Director, Property
Management at CBRE South Asia Pvt. Ltd., is
Professional Engineer (PE), Active member of ISHRAE, a
Certified Energy Auditor and an IGBC Accredited

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