User:Jvanhook44/sandbox

Overview
Heating and cooling of a building is a big part of today’s society. There are many ways to do this. The older conventional ways will always work but the Green Revolution has caused a lot of research to be done to make everything more energy efficient. Chilled beams have become an answer in the last few decades. Active Chilled Beams (ACB) have primary air being transported to the chilled beam that is mixed in a plenum with air that is being induced from the room. This mixture of air is then heated or cooled by pipes containing water. This water arrives to the chilled beam at a certain temperature to heat or cool the air that is then released back into the conditioned space. Passive Chilled Beams (PCB) are very similar except there is not primary air inducing the convection process in the chilled beam. Passive chilled beams rely solely on the convection process. The warmer less dense air will rise to the ceiling space where it will then be cooled by the chilled beam and released as a denser, cooler air. The cool, less dense air will then fall toward the breathing zone.

History
A Norwegian Engineer by the name of Gunnar Frenger, invented a device that used mechanical equipment to radiate heated and cooled air from the ceiling space to control temperatures in the 1940s. His designs were then taken and advanced by adding the primary air flow to the mechanical equipment, in the early 1970s in Gothenburg, Sweden. This was said to be the first step towards today’s ACB. Chilled Beams have been considered one of the most common ways to heat and cool buildings in the Europe since the invention of them but it hasn’t been until the last decade for North America to begin installing these energy efficient methods.

Advantages
The move to chilled beams came because we were searching for more efficient ways to condition spaces. The use of water increases the efficiency greatly. Trane Inc., Heating, Cooling and Ventilation experts since 1913, have said that a 1” pipe containing water around 60˚F carries as much energy as an 18”x18” duct carrying air at the same temperature. Water is a better insulator than air allowing it to be able to keep that energy. With the chilled beams using this water as the energy transport, the amount of primary air being supplied to each room will be less. All duct work will be smaller, along with your Dedicated Outdoor Air System (DOAS). The DOAS is what takes air from the outside, cleans and purifies, and then fans supply this air through duct work to the conditioned rooms. With an active chilled beam, each room will need a certain amount of outdoor air to help achieve the sensible heating/cooling load. Because the chilled beam uses convection processes in the room the amount of air from the DOAS unit does not have to be as large. The smaller duct work also allows for shorter ceiling space allowing for shorter buildings. Chilled beams are also quieter than your traditional Variable Air Volume (VAV) systems. The velocity of air moving through the large duct can get very loud but with water being the main transport of energy the system is arguably silent. Comparing the ACB system to a VAV system, the ACB uses significantly less energy. There are fan energy savings because each room does not need quite the primary air flow so the fans in the DOAS are smaller and higher chiller efficiencies because the higher water temperatures being delivered to the chilled beams.

Disadvantages
Chilled beams are great energy savers but with every positive there is a negative. Chilled beams do have a higher installation cost than your typical duct work connected to diffusers. The chilled beam themselves are where they tend to get pricey along with all the copper pipe used to transport water. You will save money on other mechanical equipment such as your chiller, DOAS, duct, etc. but because chilled beams are not fan driven it is harder for them to reach the cooling capacity of the respective VAV system. Where you might have one diffuser in a room that only takes up a 24”x24” ceiling tile space, that room might need two chilled beams that can be up to 24” wide by 96” long. Chilled beams also have restrictions on certain places for applications. For example, they are not recommended for an area that has a high humidity, such as gymnasiums, theatres, and cafeterias. Chilled beams typically are not installed with a condensate drain system and therefore if the dew point of the room rises above the surface temperature of the chilled beam coil then there will be condensation on the coil. The convection process of a chilled beam does not allow for filtration of the air that came out of the room. This recirculation process eliminates the possibility of having a ACB system in hospitals and locations that need ventilation/filtration. If the chilled beam is applicable, in the long run though, there is energy savings that will offset the input costs of the chilled beams.