Actuators for Chilled Water Valve | DDC Commercial Systems

Actuators for Chilled Water Valve Control Commercial HVAC SystemsActuators for Chilled Water Valve – These chilled water actuators control the flow rate for a chilled water system in a data center. There are various sequence of operations for chilled water systems and the sequence of operation is usually always different from one chiller plant to another chiller plant. (more…)

Air Management in Hydronic Piping Loops

Air Management in Hot and Chilled Water Piping Loops
Air Management in Hydronic Piping Loops - This is a secondary chilled water pump in a large pump room designated for pumps and piping in a data center. After a few minor tweaks and corrections these pumps all operated flawlessly. There was very little issues with the secondary pump start-ups. Unlike the primary pumps where cavitation was encountered on the primary chilled water pumps and the condenser water pumps for the chiller. The diagnosis for the cavitation of the primary pumps and the condenser water pumps was that the loops were not properly purged. This caused those pumps to cavitate. The secondary pumps, pictured here, did not have that problem. Kudos to the team that purged the loops on this side of the chilled water system.

That was an initial installation issue. It was also a lesson in priming the system to ensure all the air purged from the loop. After all, cavitation in the pumps can cause damage to the pumps. Even after the initial installation purge, it is important to ensure air does not build up in the water piping loop. To do this we need a few devices to help purge the air before it becomes a problem. This will prevent nuisance problems such as hydronic air block in branch circuits of the loop. It will also prevent and damage that may be caused by pump cavitation as a result of too much air in the system.


Cooling Tower Fan | Commercial HVAC

Cooling Tower FanThis is a HVAC chilled water system cooling tower fan for a large chilled water system. Four large cooling towers for two chiller plants in a data center. Data center cooling systems generally are redundant not only for emergency situations but also for maintenance. The cooling tower fan typically has vibration switches installed in the fan assembly to shut the fan off in the event of too much vibration. A fan this large (approximately 6 foot diameter) needs to be balanced to prevent vibration that could possibly shake the cooling tower apart and create a safety hazard for workers. The fan is driven by a variable frequency drive that ramps the cooling tower fan up and down depending on demand. (more…)

Large Condenser Pump for a Chilled Water System

Large Condenser Pump for a Chilled Water SystemLarge Condenser Pump for a Chilled Water System

This large HVAC condenser pump serves a new chiller located in a data center. This pump pumps condenser water through the condenser chiller barrel and to a cooling to reject the heat absorbed in the chillers evaporator barrel. The pump works to move the water from the chiller to the cooling and then back through the chiller again. The water is diluted with a glycol solution to prevent freezing in the winter time when the chiller needs to run at low ambient temperatures. (more…)

DX CRAC Unit Condensers | Critical Facility HVAC

DX CRAC Unit CondensersDX CRAC Unit Condensers | Critical Facility HVAC

DX CRAC Unit Condensers | Critical Facility HVAC - Most data centers do not utilize HVAC DX (Direct Expansion) CRAC units or air conditioning but instead use chilled water systems to provide cooling for the data center. In smaller buildings such as remote telecom buildings DX air conditioning systems are used to keep the equipment cool and operating efficiently. A DX CRAC Unit uses vapor compression refrigeration to provide cooling with a chemical refrigerant versus a chilled water system that utilizes chilled water from a chiller. CRAC Units or Computer Room Air Conditioners also serve telecom facilities for telephone services including cellular telephone facilities in remote locations. The CRAC units that serve telecom facilities in remote locations are typically DX CRAC Units that have utility back-up by stand-by generator so that if the utility fails to provide electricity for whatever reason the stand-by generator kicks on and provides power so that the telecom facility can remain on line. (more…)

Chilled Water System Basics | HVAC Cooling

Chilled Water System Basics
Chilled Water System Basics - Chilled water systems work much the same way as direct expansion systems work. The exception is they use water in the coil rather than refrigerant. Technically speaking, water can be classified as a refrigerant. Chilled Water systems can be rather complex and many chilled water systems are found in commercial and industrial applications. There are some chilled water systems used in residential applications. (more…)

Trane Chilled Water Systems – Multi-Zone Air Conditioning Systems

Trane Chilled Water Systems – Multi-Zone Air Conditioning SystemsTrane Chilled Water Systems – Multi-Zone Air Conditioning Systems - This Trane HVAC chiller serves four different apartments. Chilled water systems offer a great way for multi-zone air conditioning. From small apartment buildings to large commercial buildings chilled water systems can serve multi-zone air conditioning systems. From one air conditioning zone to hundred the only limitation is the size of the chiller. If the air conditioning zoning system (the load) is matched up with the right sized chiller (in tons) the system will serve all air conditioning zones and keep all the occupants comfortably cool. Chilled water systems can also be integrated with the boiler system so that the same system can be used for heating and cooling. A good control system will add efficiency and more comfort to the system. (more…)

Plate Heat Exchanger and Free Cooling

Plate Heat Exchanger and Free Cooling - This plate heat exchanger is used in a data center for a chilled water system and is a chilled water economizer. Plate heat exchangers are used in marine applications, industrial processes including chemical processing systems, food processing, and many HVAC applications including chilled water applications, hot water applications, and economizer applications. (more…)