If you work in a conventional office building, the Heating, Ventilation, and Air Conditioning (HVAC) systems provide comfort to the building’s occupants. Other buildings, like hospitals, research labs, and high-tech manufacturing plants require a lot more than just keeping the inside air at the right temperature and humidity. No matter how elaborate or simple the HVAC systems in a commercial building are, it’s likely that their operating costs will represent more than 50 percent of the total energy bill. That makes designing energy efficient air control systems for commercial buildings a great way to reduce ongoing operating costs for the building overall. Here’s a list of eight technologies that a smart HVAC designer can use to improve the safety and comfort of a building’s occupants while reducing the cost of operation.
The purpose of a well-designed HVAC system is to distribute the right amount of heated, cooled, dehumidified, and filtered air to the right places at the right time. Designers take pains to calculate the amount of makeup air that a system requires, and they determine the size of ducts and fans in order to make sure that every area in the building is properly heated, cooled, and ventilated. If the ductwork isn’t sealed properly, air leaks can throw the calculations off. Air leaks can force the occupants to raise or lower their thermostats in order to get the amount of heating or cooling they desire, increasing costs further. One of the least expensive improvements you can make to any air control system is to ensure that the ducts are sealed properly when they are installed, and to have a regular inspection that makes sure they stay that way.
Demand Controlled Ventilation
Depending on the number of occupants in a building at one time, the proper amount of ventilation can vary quite a bit. Air control systems can be fitted with carbon dioxide sensors and other space sensors from companies like Phoenixcontrols.com that avoid over-ventilation while still maintaining healthy and comfortable levels of fresh, conditioned air. The sensors only call for additional conditioned air when needed, and costs go down when the HVAC doesn’t run as often when the building is only partially occupied.
Electronically Commutated Motors
For most air control systems, the fan motors are either off or on. Others have a series of steps in their fan speeds. If you have truly variable-speed controls on your equipment, the blowers will run at exactly the speed necessary to deliver the amount of air required for safety and comfort. When blowers run at a lower speed, they consume less energy. Variable speed blowers also solve the problem of having too much heating or cooling when the unit is on, and then too little when it’s off.
Dedicated Outdoor Air Handling
When an air HVAC system sends conditioned air to every corner of the building, it must receive an equal amount of return air. In order to keep air in the building fresh, most large-scale HVAC systems also bring in fresh air from the outside. It’s often necessary to remove excess moisture from outside air before it’s circulated through your HVAC system, because moisture increases the load on a cooling system. If you have a dedicated outdoor makeup air system, you can dehumidify fresh air before introducing it to the makeup air system, which will save money and wear and tear on your entire HVAC system.
When stale air is exhausted from the building, you can use it to condition the air that is being brought inside to replace it. This can result in a savings in heating and cooling costs. It’s also preferable to an energy saving strategy of simply sealing all air leaks in the building and only using makeup air from inside the building. Keeping conditioned air in the building longer can save money, but it can also lead to a buildup of stale air that’s been recirculated too many times.
Thermal Energy Storage
This strategy involves the introduction of a storage material, often a reservoir of water, that lets you extract heat from it during off-peak energy hours and then use it to cool the air during high cooling load periods. Since electricity rates are lowest at night when buildings are largely unoccupied, you can save money with no disruption in the normal operation of the building.
Zero-Degree Heat Pumps
Heat pumps can work at temperatures as low as 0 degrees Fahrenheit. The ability to capture heat even in very cold climates allows heat pumps to achieve energy efficiency ratings of greater than 100 percent. That’s because heat pumps don’t use energy to create heat, they simply transfer it from the outside of the building to the inside. During the summer months, the process is reversed, but the savings remain.
It is possible to supply small areas of a space with substantially different heating, cooling, and ventilation levels than other areas without partitioning them off from the rest of the building. This virtual climate zone is used in large open areas like warehouses where personnel cluster in one area and need to be kept warmer or cooler than the ambient air in the rest of the structure. Microenvironments can lead to increased levels of comfort for the building’s occupants, which contribute to higher productivity. Setting up a microclimate HVAC system can be costly compared to conventional systems, and they requires careful detailing, but they save a lot of money over the life of the installation.
These technologies are available right now, and can be integrated into many existing HVAC systems. They can also be specified to improve energy efficient air control systems in new construction. It’s a smart idea to factor in long-term energy costs when you’re doing an analysis of the cost of any new system or upgrades of an older system. It’s also smart to put regular maintenance at the top of the list of ways to improve occupant comfort while saving energy and money. It might be possible to improve the performance of an existing system simply by having it cleaned and inspected for trouble spots, and it will cost you a whole lot less than adding additional equipment to cut energy use.