The ems will know immediately if a belt breaks, for example. Moreover, it will indicate exactly which unit and exactly which belt. Otherwise, the building owner would only know if he had a problem after someone complained.

“You will respond to problems much quicker,” said McDonald.

To “match the right system to meet the customer’s needs,” he continued, Brewer-Garrett offers Novar, Trane, and Johnson Controls systems. McDonald knows the latter quite well, having worked at Johnson Controls for 10 years.

Typical projects, critical questions

The contractor installs systems in “small buildings of 10,000 sq ft to multi-building campuses,” said McDonald.

The ems can control a central plant, chillers, all hvac equipment, lighting (which accounts for 60% to 70% of energy usage), security systems, and fire alarms.

John Mancinelli, manager of the Controls Group for Brewer-Garrett, noted that sometimes the ems incorporates some of the above devices, but not all.

He said two questions should be asked:

1. Do we want to put this on an ems?

2. How much will it save?

Much improved

Mancinelli said that the ems was originally there “to turn things on and off.” Today, it is much more sophisticated.

Ten years ago, McDonald pointed out, an ems could not cost-effectively control variable air volume (vav) systems by electronics. Now it can.

“Reliability and lifecycle are way up,” said Mancinelli.

Older control systems would provide control at up to +3° or +4°F above the setpoint. Current systems control to within +0.5°, to provide added comfort and reduce costs.

As the price of electronics has decreased, so has the price of an ems. McDonald related that systems are one-half the price that they were seven years ago.

Modern chiller units are equipped with microprocessors to which the ems interfaces. “Controls on a boiler are not nearly as sophisticated,” said Mancinelli.

Just about the most complex, he noted, are controls that adjust the temperature of hot water based on how cold it is outside.

To meet outside air requirements, the ems can bring in air as needed to meet code. For the morning warmup, as it brings the temperature of the building up to 72°, there is no need to bring in outside air initially until the building is occupied.

Minimum required outside air is then added as CO goes up.

Remote fix for profitable service

Brewer-Garrett has about 140 ems out in the field that they monitor. McDonald said, “The ems plays a big part in our service business.”

The contractor has two-way communication with each system via computer. If very cold weather is forecast, the staff will randomly check the temperature at customers’ buildings. These checks can be done from the office or on the road using a laptop.

“The software is much more powerful now and we can gather information a lot of different ways,” stated McDonald.

Mancinelli remarked that the firm can “sometimes solve problems without even sending a mechanic.”

Regarding the use of open protocols in his customers’ facilities, McDonald said that BACnet and LonWorks are “becoming more prevalent.”

But he noted that they aren’t growing as fast as originally expected. “A lot of companies are protecting their own protocol.”

Justifying cost

Brewer-Garrett offers all its customers service contract support. But some, such as hospitals and universities, are vendor independent said McDonald, and prefer to have their own staffs take care of the equipment.

In justifying the cost of a new ems system, McDonald said payback (typically 3 to 5 years) is only one criterion. “The ems allows building maintenance to operate more efficiently and provide more comfort.”

He concluded, “An ems does more than just manage energy.”