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4  FM quick reads on Building automation

1. 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.

2.  Energy Management System Can Streamline Facility Maintenance Tasks

Today's topic concerns the way an energy management system can help improve maintenance.

The two biggest reasons that an energy management system are installed are to improve occupant comfort and to reduce energy costs. But there's a third important benefit that, while it may be difficult to quantify, should not be discounted, says the California Energy Commission. That benefit is improved maintenance.

A properly programmed energy management system can help maintenance in several ways. Simply being able to monitor building systems from a central location is a big plus for maintenance. Instead of having to go to a specific unit to try to determine what's wrong, the maintenance staff may be able to use the energy management system to gather information. What's more, energy management system alarm monitoring makes it easier to detect abnormal conditions and equipment problems, reducing the time it takes to respond to those problems.

What's more, the energy management system can capture data about equipment runtime and use that information to automatically generate work orders for scheduled maintenance, which can help extend the life of equipment. And it can monitor and capture trends for system parameters that are used to troubleshoot building systems and equipment.

Finally, the energy management system can automatically make the change to daylight savings time and back, saving staff time and preventing problems.

3.  DDC Controls Make Retrocommissioning Easier, More Essential

Today's topic is retrocommissioning.

The move to direct digital controls (DDC) has made retrocommissioning more important. As controls have become more complex, the chances for things to go wrong have increased. At the same time, however, DDC systems are easier to commission than their pneumatic predecessors.

For one thing, it can be more cost effective to work on buildings with DDC than with pneumatic controls. For example, a commissioning agent can use the trending capability of a building automation system rather than work with data loggers. And it's easier to make changes in software than to tear out hardware.

Software-based controls also make it possible to make changes and note what happens. A control sequence or setpoint could be adjusted on screen, and the results observed. When changes like those are made, it's essential that someone from facility operations be involved. The retrocommissioning agent might recommend a change, but it's up to the facility staff to approve and implement the action.

4.  Soft Skills Are Important in Retrocommissioning

Today's topic is the importance of soft skills for retrocommissioning.

Retrocommissioning — the commissioning of existing building systems — can save a significant amount of energy for a relatively small investment, in part by improving the way controls operate. But in some facilities, any change in operations may seem like a risk - a risk that isn't worth taking.

That was the case at the University of Illinois - Urbana Champaign. The University decided to retrocommission buildings with the highest energy use. But the retrocommissioning teams sometimes met with resistance, even though departments housed in those buildings were going to be charged back for energy use. Some departments were worried that changes in the way the facility operated might cause harm to experiments that had been going on for years - even decades.

Working with the staff in those buildings took patience and persistence. The retrocommissioning team made small changes, then let everyone see the results. They also had to educate occupants about the impact that their behavior could have on energy use. In one lab, encouragement to close fume hood sashes reduced energy costs by $30,000 in one month.

Being sensitive to occupant perceptions paid off, not only in energy savings, but also in customer satisfaction. By the time the retrocommissioning team left, building occupants were happy they'd come.


Building automation , energy efficiency , HVAC , controls

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