4  FM quick reads on HVAC

1. 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.

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.

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.

Retrocommissioning Can Solve Three Common Controls Problems

Today's topic is retrocommissioning.

Controls that weren't properly designed or programmed, or that have been overridden or otherwise gotten out of whack, can increase energy costs while making building occupants uncomfortable and shortening the life of equipment.

Most of the issues that retrocommissioning identifies have to do with controls, say experts. Perhaps the most common problem is scheduling. Often equipment is running more than it needs to. A pump, for example, may be running longer than it should to satisfy building demand - possibly even all day and night — without anyone knowing it. Not a glamorous problem, perhaps, but it's expensive. The pump will wear out sooner than it should; meanwhile, energy dollars will be wasted.

A second big category of problems has to do with economizer dampers. They may be stuck in one position or there may be errors connected with the control sequences or the sizing of dampers.

Setpoints - supply air temperature and pressure as well as condenser and chiller water temperature - are a third common opportunity for improvement. Retrocommissioning can tune those setpoints to match demand more closely. Retrocommissioning — or recommissioning, if the building was commissioned in the past — is especially important in multitenant buildings and other facilities that undergo a significant amount of change.


HVAC , Retrofits , Facility Management

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