Data Center Perforated Tiles for Cooling Servers - There is a lot to consider with perforated tiles in data centers and depending on who you talk to you will get different answers. The server floor in a data center is typically built on a raised floor with cold air being pumped under the floor by large CRAH (Computer Room Air Handlers) or CRAC units (Computer Room Air Conditioners). (more…)
Honeywell Temperature Fan Limit Switch Control – The fan limit control turns the fan on and off in furnace applications. It works off of temperature and also provides a high-temperature safety limit. This is a switch, actually two switches, which turns the furnace blower on and off based on the temperature of the heat exchanger.
A helical bi-metal probe extends from the back of the fan limit control. This probe is located inside the heat exchanger and the bi-metal of the probe reacts to temperature.
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. (more…)
Outside Air Temperature-Humidity Sensor - The outside air temperature sensor uses a thermistor to read the outside temperature. This sensor also senses humidity using a humidity transducer. The temperature and humidity readings are collected by a direct digital control system and used in a program. Aside from using this information for user interfaces, the information is also used in a control program to open and close an outside air damper. (more…)
The Mercury Switch Thermostat | HVAC Control - Mercury switch thermostats are not available for purchase in many states. They have been banned because they contain mercury, and it is important to properly dispose of these thermostats that contain mercury if they are changed out for newer digital thermostats. Some many homes and businesses still have these thermostats in use so we will offer a brief of how these thermostats work including the components inside the thermostat. (more…)
Aquastat is the gray box on the left while the circulator is the black pump on the right.
Aquastat Temperature Control - The boiler aquastat controls the temperature of the water inside the boiler jacket. The boiler aquastat is a device to a boiler like a thermostat is to an air conditioner, heat pump, or gas/oil furnace. A boiler aquastat controls the temperature inside the boiler just as the thermostat controls the temperature for an air conditioner or heat pump.
The boiler aquastat will turn the burners on and off and also controls the circulator pump on a hot water boiler system.
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Have you ever wondered how Heat Pumps work? Heat Pumps can be a very economical way of heating and cooling your dwelling. It depends on geographical location and the cost of electricity in your area. The volatile costs of natural gas, propane, and oil have enabled these conditions. Conditions where it can be cheaper with a heat pump than with fossil fuels.
There is a common conception that a heat pump blows cold air.
While this can be true in some cases it is not true. If a heat pump is blowing cold air when in the heating mode then it has a problem. A problem that needs to be corrected. Even when the outside unit kicks into the defrost mode the unit should provide adequate heating.
Heating to heat the zones which it serves. Again, if it is not providing adequate heating then it needs to be looked at for a technical problem. A problem that needs correcting. A well-designed system, working properly and efficiently, can provide competitive and economical heating. (more…)
R-134A Refrigerant Pressure Temperature Chart - R-134A is an inert gas also known as Tetrafluoroethane, and for air conditioner systems. Furthermore, R134A is a chemical refrigerant in automotive and domestic use air conditioners. Additionally, HVAC Systems such as chilled water systems in both commercial markets and industrial markets. You are very familiar with R134A if you are either an automotive mechanic or a chiller mechanic. R-134A uses the names Tetrafluoroethane, Genetron, or Puron, among other names depending on the manufacturer. Finally, The pressure-temperature chart represents the average pressure-temperature relationship of refrigerant R-134A.
Programming DDC Logic 2 - The analog network input is similar to an analog input except this input is not hardwired to the local controller but on a remote controller in the network. It is very important that the communication works effectively for this analog network input to work. An example of this is the outside air temperature which is hardwired to a DDC controller in the penthouse of a multistory building.
The building engineer only wants the boilers to fire if the outside air temperature is less than 55° F. Instead of having an outside air temperature device hardwired to the boiler controller an analog network input can be placed into the boiler controller program and linked to the outside air temperature reading which is in the penthouse controller where the outside air temperature thermistor is hardwired. This saves devices and wires necessary for optimum control.
Hot Water Boilers - HVAC Hydronic Heating - People who use boilers for their primary source of heat report that they love the kind of heat that a boiler provides, whether they have a hot water steam boiler. If you thought that there is only one type of heat, you might want to reconsider. All you have to do is add adjectives to the beginning of the word heat. There is:
Boiler heat will give you even, draft-less heat. That is opposed to “drafty”, uneven heat that some heat pumps and forced air systems provide.
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