Mechanical

Chillers are the heart of a cooling system in a large building including condominiums and large commercial buildings. They use power to drive compressors to compress refrigerant, cool the refrigerant, which allows it to expand to cool (chill) water. The chilled water is then used to cool the building through heat exchangers and coils. Heat from the chiller is rejected through a cooling tower located on the outside of the building.

In the last couple of years, chillers have gone through significant improvements to increase their efficiency, therefore reducing the amount of energy to produce the same amount of cooling. Improvements have also been made in the operation of the chillers with the use of computer controls and sophisticated interfacing with the Building Automation Systems. Older chillers’ were 0.85 to 0.80 kW/Tonnes of cooling while the newer chillers are significantly more efficient around 0.55 to 0.45 kW/Tonnes of cooling.

There are many different types of chillers; centrifugal, screw, semi-hermetic(reciprocating), scroll, to finally absorption chillers. Each chiller type has it particular application and efficiency for a type of application. New types of chillers have frequency drives to regulate the speed of the motor thus increasing or decrease the amount of refrigerant flow and some use magnets instead of oil and bearings to support the shaft and motor.

Chiller sizes vary from 1 tonnes, to cool a house to thousands of tonnes to cool large high rise buildings or multiple buildings. Some installations will use multiple chillers to have redundancies while others will use multiple compressors on a single chiller.

Different chillers may use different refrigerants with 134a being the most popular but others are R123 and R410. The types of refrigerant depends on the size, type, and application of the chiller along with the required supply temperatures. Normal building cooling requires chilled water to be supplied between 42 0F (5.5 0C) to 48 0F (9.0 0C) for proper cooling and dehumidification. Other applications may require lower temperatures.

Boilers have been around for a very long time, burning everything from wood, oil and natural gas to produce hot water to heat buildings. We have come a long way from an open flame heating a kettle full of water, to very sophisticated burners to the materials used in the boilers to the computer controls to manage the operation of the boilers.

Over the many years boilers have drastically changed from a very large, heavy and inefficient piece of equipment to a very highly developed instigate piece of energy efficient equipment. Boilers have come from being 60% to 80% efficient to modern day boilers being 86% to 97% energy efficient. Gone are the days of thick heavy cast iron welded boilers to high tech cast iron that is flexible, to thin copper and stainless steel materials.

The newest styles of boilers are condensing boilers which can produce the highest efficiencies of up to 97% depending on the water temperatures. Once the hot water temperatures drop below 130 0F (55 0C) efficiencies start to climb from 86% up to 97%. In order to produce low water temperatures below 130 0F (55 0C) you must have a system that can use low hot water temperatures and a boiler that can withstand high pH levels within the boiler heat exchanger.

There are different burners that a boiler can incorporate in it’s design including atmospheric, fan induced, and different styles of power burners. Each having it’s cost and efficiency benefits. Also different burners will be able to control amount of Nitric Oxide that is being discharged which maybe critical when designing large boilers in high density or sensitive areas.

Building Automation Controls (BAC) systems have been changing in the last 10 years as fast as computers. Before Direct Digital Controls (DDC) pneumatic controls (compressed air) were used predominantly for decades. With the onset of DDC, BAC systems have been changing and becoming more complicated and more exact. Considerable changes have been made in controls and their costs, in order to control more systems to the required environment using the least amount of energy.

With today’s technology every temperature in the building from the space to the heating and cooling loops, to outside air intakes and exhaust can be monitored and controlled. No longer is outside air brought in at a constant rate during the day, CO2 can be monitored in the building and bring in just the needed amounts of outside air thus reducing energy costs and increasing comfort.

There are many other systems that can be controlled like lighting, with motion and light harvesting sensors, security, CO monitoring, for garages, and just about anything else you can think of in a building.

Heat Pumps, have been around for many years and have been getting more energy efficient. There are several different types but the two most common are air and hot water heat pumps. Water is most commonly used in a commercial or high rise residential building. In the heat pump unit there is a refrigeration compressor, two heat exchangers (one to the building loop and one passing air through it to cool/heat the air, supply air fan, and a reserving valve. The unit is capable of cooling the supply air by discarding heat into the building loop, typical air conditioning unit, but when the reserving valve change the flow of refrigerant the unit is capable of heating the supply air by obtaining heat from the building loop. Therefore in the summer the heat pump loop warms up and is cooled via a cooling tower and in the winter time the heat pump loop is cooled and is warmed by boilers.

Ground source heat pumps are the same as the system just described above but the heat pump loop is heated and cooled via the ground. Deep holes are drilled into the ground to extract heat or inject heat from the heat pump loop into the ground, as the ground temperature is always in around 55 0F (13 0C). Therefore no cooling tower or boilers are required to operate this system, making it a very energy efficient system and it a very environmentally sound system.

Electrical

Lighting, can be one of the largest usage of electricity in a building besides the HVAC systems. It is one of the most noticeable system as everyone must have light to see the task at hand. Lighting technology has come a long way from the first incandescent lamp. Fluorescent lamps have progressed from T12 to T8 to T5. The ‘T’ stands for Tube while the 12, 8 & 5 is the diameter of the lamp in 8th of an inch. Along with the changes is diameter the technology driving the lamps, the ballasts, have also changed therefore making the T8 more energy efficient that T12 and the T5 more energy efficient than the T8. There are many different lamps for many different uses, like High Intensity Discharge (HID) lamps for exterior and warehouse lighting. The HID lamps have also gone through many variations to many to discuss her, but needless to say each iteration has become more energy efficient with the ???? lamp being the preferred current lamp to use.

Emergency Generators, can be installed in a building so that power will be available during a power outage or during a fire. They typically power emergency equipment like, emergency lighting, exit lights, fire alarm systems, an elevator and other equipment deemed mandatory for the safety of the buildings’ occupants. In this regard, some of the rules have changed over the last number of years, so you may find that your existing generator does not now comply with the required local codes.

Fire Alarm Systems are required by code in the larger buildings or in buildings where there is a high density of people.

Energy/LEEDS

Building Science

Project Management