Hot Water Boiler Economizer PreHeater | Energy Efficiency
This is a hot water economizer and is a big preheater for domestic hot water use. This boiler plant serves a large community for heating and domestic hot water use. Domestic hot water is used for showers, washing dishes, laundry, ect, ect, ect…. The cold water supply from the city is routed through the economizer to be pre-heated before it goes through a heat exchanger and then the hot water storage tank. This system saves money because it uses the exhaust gases from the boiler to pre-heat the city water supply which is normally 50 degrees Fahrenheit. The exhaust gases from the boiler would otherwise be vented to the atmosphere and would be considered wasted heat. (more…)
Large Cooling Towers Serving a Data Center and Commercial Building
How Cooling Towers Work
How Cooling Towers Work – Cooling towers use evaporation cooling to cool condenser water from a chiller. Water is pumped to the top of the cooling tower where the water flows down some flow plates to the cooling tower basin. As the water is flowing down the flow plates air is pulled through the plates and over the water where it releases heat through evaporation. After the water has released the heat it is then pumped back through piping to a chiller barrel where it absorbs more heat and then returns to the cooling tower. Because of evaporation the cooling tower system is equipped with a float that controls the level of water in the basin to prevent the water from evaporating away and giving the system a shot of fresh water called make-up water. When the float drops below a predetermined level a valve is opened introducing make-up water into the cooling tower system. Some cooling towers utilize a solid state type of water leveling system and these water leveling devices need to be calibrated to maintain precise levels in the tower. The make-up water is generally supplied from the city water supply or even a well.
High efficiency cooling towers have variable frequency drives that can be controlled by a reset schedule based on outside ambient air temperature. This feature saves energy by allowing the fan to run at lower speeds based on lower temperatures outside. What type of fan for the system and the complexity of the fan type will depend on the type of cooling tower and its intended design.
HVAC Cooling towers also require water treatment chemicals and regular maintenance for cleaning, belt and motor maintenance. Some cooling towers use filters to filter unwanted particles from the water. Most cooling towers require some kind of water treatment whether it is glycol for operation in colder temperatures or for water quality to treat for algae or other biological things that can grow in water. (more…)
Heat Exchanger & Domestic Hot Water Storage Tank – In the front is a commercial heat exchanger. Behind the commercial heat exchanger is a domestic hot water storage tank.
The supply water from the city is directed through the heat exchanger where it is heated to a set point temperature. This is usually 120 to 130 degrees Fahrenheit. 180-degree water from the boilers run through tubes inside the heat exchanger while the cold water runs through the inside of the heat exchanger in separate channels outside the tubes where the hot boiler water is. The water is heated and then delivered to the community where it used for showers and washing dishes and other hot water uses. (more…)