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Staying ahead of your aging HVAC

2019.07.15 Aggreko

Staying Ahead Of Your Aging HVAC


Climate control is a necessity for just about any building, whether residential, commercial or industrial. Failing to keep things warm or cool enough leads to lost productivity, damaged goods and equipment - even shutdowns. This makes it essential that you have a top-notch HVAC system installed.

No system, however impressive, can last forever. So what happens when individual components and units start to age? How do you know when to replace and when to repair? And how do extend the life of your HVAC system to stave off the inevitable? 

What Does the HVAC System Do? 

Heating, Ventilating and Air Conditioning (HVAC) systems deploy heat transfer, thermodynamics and fluid mechanics principles for all kinds of temperature control purposes, including comfort heating and cooling, keeping data centers and equipment in control rooms from overheating, getting rid of stale air and circulating fresh air in a building.

The term HVAC covers everything from our home air conditioning units to the huge, complex systems installed in offices, hospitals, schools, and industrial buildings. 

How Have HVAC Systems Evolved Over Time?

The modern air conditioner was born in 1902, when Willis Carrier drew up plans for a system that would cool production rooms at the printing plant he worked at, preventing books from being damaged in the process. 

These early versions worked by circulating cold water instead of hot water through heater coils, chilling the air that ran over it. Over time, designs improved as refrigerants replaced cold water, air conditioners and associated venting and piping shrank in size, units became much more energy efficient, and ozone-depleting chemicals were replaced with more environmentally-friendly coolants. 

Recently, the Internet of Things and associated technologies have been created and used for remote climate control, smart energy usage and performance monitoring. Today’s HVAC systems are drastically cheaper to run and far less energy-guzzling than ever before. 

How Are Today’s HVAC Systems Set Up? 

Commercial HVAC systems in large buildings use a compressor to increase the pressure and temperature of the refrigerant. The compressor then blows hot air from outside over the condenser to liquefy it, before the expansion valve changes the refrigerant into a low pressure, cool liquid. The evaporator transfers heat, turning the cool liquid into a gas that’s just warm enough to be circulated. 

How this is set up depends on several factors, in particular: whether electricity or gas is used to fuel the heating elements, the type of coolant, whether heat or cooling is delivered through ducted air or the water system, and whether or not a dedicated ventilation system is in place. 

Depending on the building, the system may also incorporate cooling towers, chillers, boilers, radiators and heat pumps that extract heat from air or water and/or rooftop units that duct conditioned air into the space inside the building.

These systems work either by using air handling units connected to ductwork that distributes heat and cool air around the building, or they may be a collection of smaller systems that operate separately, such as mechanical ventilation, radiators for heating and comfort cooling units distributed around the area. Most will also try to incorporate “passive” forms of ventilation, reducing their energy use and costs.  

What Happens As These Age?

As chillers, AHUs, air conditioners and other HVAC units age, they become less reliable. With proper maintenance, HVAC systems are designed to last between 10 and 30 years, 20 years being the average before they start to break down. 

To put this in deeper perspective, there are nearly 6,000 registered hospitals in the US, with more than 900,000 beds and a combined budget of nearly $1 trillion. That’s a vast infrastructure of HVAC that contributes to our nation’s health and well-being, and if those begin to falter, you can quickly see the detrimental effects that occur. 

When the cost of proactive maintenance or emergency repairs creeps above around 5% of the cost of replacing the unit, you need to think carefully about whether it would be more economical to simply opt for a new one.

That’s not just because you might have to pay for 20 rounds of repairs. It’s also because, while you’re stuck using sub-par units, their performance is probably slipping too, pushing up your energy costs. If you rely on HVAC for business-critical operations, leaving things too long can lead to unplanned outages and expensive shutdowns.

This is also true of the small-scale components that connect parts of a large, complex system. HVAC is typically reliant on your electrical and/or plumbing systems, so any issues with faulty wiring, outdated electrical equipment, or neglected pipes that start leaking or burst will cause total havoc.

Replacing ancient units or systems can be a huge headache, though - especially if they’re buried underground, situated on roofs or are otherwise hard to access. If these have been ignored for decades, you may also have webs of old wiring or piping surrounding them, too, which can be very fiddly to find your way through without causing damage!

What Can I Do About It?

The key here is preventative maintenance. Keep a close eye on your building’s HVAC system, conducting regular audits to check that all equipment is still fit for purpose - or whether you’ll need to replace any components. 

To start with, take a look at the water pump, drains and compressors. How old are these? Do they look like they might be nearing the end of their useful life? 

To minimize the risk of water damage building, draw up a maintenance and equipment inspection schedule, based around monthly, seasonal or annual tasks and requirements. 

Also, make sure you compile information about when each HVAC component was installed (and when it’s due to be replaced), specifications for each item of equipment (with model and serial number), equipment history record files (including dates of installation and repairs), a list of spare parts that you may need and where to source them from, air balancing reports and airflow specifications, together with blueprints and system operation places for associated plumbing, mechanical and electrical systems. 

If you have a lot of aging equipment, think carefully about whether it could work out more cost-effective in the long term to upgrade the whole system at once, or to bring in highly efficient rental equipment instead of splashing out on an expensive new one.

Whether you go down the route of upgrading, renting or carefully maintaining your existing system, the most important thing is that you intervene early to address any problems with the HVAC in your building. This helps you to prevent catastrophic equipment failure, while trimming your daily operating costs. It’s well worth making the investment now! 

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