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4  FM quick reads on HVAC

1. Questions to Ask When Renting HVAC Equipment


Today's tip comes from Jim Piper, contributing editor for Building Operating Management. When a decision has been made to rent HVAC equipment, facility managers should evaluate a range of factors when selecting a rental partner. Here are some questions to ask:
• What pre- and post-rental services are offered by the rental company?
• Are there additional charges for those services?
• Does the company arrange and pay for delivery and pickup of the equipment?
• Is engineering assistance available to help with connecting the rental equipment to the existing building systems?
• What type of maintenance support does the rental company offer, and what is its guaranteed response time?
• Is the equipment maintained by the rental company's staff or is it contracted out to a service company?
• Where is the inventory of rental equipment located? For small items, most companies stock equipment locally. For larger items, such as building chillers and cooling towers, equipment is typically stocked at regional distribution centers. Depending on where those centers are located, the time and cost to deliver equipment may be excessive.
• What is the rental company's policy regarding replacing and updating equipment? In the past, it was not uncommon to find that companies were willing to rent out practically any age equipment as long as it was still operating. As could be expected, the older the equipment, the less reliable it was. Today, most rental companies tend to keep equipment for a period of time well short of its rated service life. That approach reduces operating costs while allowing the companies to provide the most advanced equipment possible. For the facility manager, there is the added benefit of greater reliability.


2.  Occupant Input Can Aid HVAC Retrofits

Today's tip comes from James Piper, contributing editor for Building Operating Management.

One of the goals of any HVAC retrofit is to improve the level of service. While FMs might understand the technical problems with existing HVAC systems, they will not fully comprehend the needs of building occupants unless they get them involved in the retrofit process. Occupants are the ones that understand their operations best. FMs will not know what system will best meet their needs - indeed, they might not even have a good understanding of what their HVAC needs are - but occupants will give FMs a clearer understanding of what the HVAC system will be expected to do.

Building occupants are also good sources of information on the performance of existing systems. Frequently, they are aware of problems that go unreported to building staff. That information is often crucial in setting priorities for HVAC system retrofits.

There's one other reason to get occupants involved: HVAC retrofits can be disruptive. They can require temporary relocation of occupants. Heating or cooling service may be disrupted for days or weeks. A schedule of moves and outages will have to be developed. Without the cooperation of occupants, retrofits can turn into scheduling nightmares.

3.  Retrocommissioning Benefits Include IAQ, Longer Equipment Life

Today's topic is retrocommissioning.

Energy savings is a substantial and important byproduct of retrocommissioning, say experts, but it's not the only benefit. Indoor environmental quality is another big gainer. With controls functioning better, for example, occupants may have the benefit of more stable temperatures, which could cut hot and cold complaints. And the system is more likely to bring in the right amount of outside air.

Longer equipment life is another significant benefit. That's especially true of valves and dampers controlled by an actuator, which suffer excess wear and tear if they are being opened and closed more often than necessary.

Increasingly, another factor is likely to point to retrocommissioning: greenhouse gas emissions reduction. Lawrence Berkeley National Labs says that commissioning of all sorts, including retrocommissioning, can provide large reductions in carbon emissions. Commissioning, it says, is "arguably the single-most cost-effective strategy" for cutting greenhouse-gas emissions from buildings.

4.  Water Treatment Programs Can Solve Three Problems

Today's tip comes from James Piper, contributing editor for Building Operating Management.

When HVAC water circulation systems go unattended, problems can develop rapidly. If those problems are not swiftly detected and corrected, they can cause downtime, reduce operating efficiency and shorten equipment life. Proper water treatment is warranted. Without proper water treatment, both open and closed systems are at risk for three types of problems: corrosion, scale and biological fouling.

Corrosion is the process of metal dissolution. Uncorrected, it can lead to the loss of system integrity.

Scale occurs when suspended solids precipitate out and become attached to interior surfaces of pipes and heat transfer equipment. Scale can significantly reduce the efficiency and capacity of the entire system.

Biological fouling occurs when bacteria, fungi and algae grow in the circulating water. Uncorrected, it can foul heat transfer surfaces, plug lines and contribute to corrosion.

Water treatment requires careful planning, a commitment of resources, proper training of maintenance personnel and a focus on safety. But a properly implemented program can reduce or eliminate the effects of corrosion, scale and biological fouling.


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HVAC , equipment rental , chillers

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