Compressor Rebuild | HVAC Heating and Cooling Refrigeration

Refrigeration - HVAC Compressor Rebuild

Rebuilt Reciprocating Compressor

Compressor Rebuild – This freshly rebuilt reciprocating compressor is destined for a large commercial chiller. Chillers chill water for air conditioning. Compressors compress refrigerant vapor and pump the compressed refrigerant to the condenser to be condensed into a liquid. The compressor provides compression which is an integral part of the refrigeration process. The old compressor was condemned for electrical burn out. The windings in the old one burned up and caused the circuit breaker to trip. (more…)

Glycol Feed System for Chiller Condenser Water Loop | Antifreeze Protection

Glycol Feed System for Chiller Condenser Water Loop

Glycol Feed System for Chiller Condenser Water LoopGlycol is like antifreeze and is used in chilled water piping loops to prevent freezing. Everyone knows when the pipes freeze they also break and start leaking. Having antifreeze in a chilled water loop is important to prevent freezing. So, how do you keep antifreeze in the loop when the water/glycol mix goes out to the cooling tower and there is a loss of water/glycol through windage or drift? Meet the glycol make-up unit where it can automatically be added to the loop and prevent freezing. Antifreeze make-up units range from automatic units that will inject the antifreeze right into the loop to manual units that require an operator to control the process of adding antifreeze to the water loop. These make-up units make it easy to add it to the loop without having a shut-down of the chilled water loop it serves so the loop can continue to run while the glycol is injected directly into the loop. The loops are designed to work at low ambient temperatures need the water/glycol mix to prevent freezing especially for critical facilities like data centers that need to remain operation no matter what the outside temperature conditions are. Percent of antifreeze to water depends on the expected operational temperatures outside so the mix is important for expected operating temperatures. An example of this is listed in the following table (follow equipment manufactures instructions for the recommended mix of antifreeze to water for temperatures):. Each loop requires a different ratio of mix based on ambient conditions, flow rates and other factors for determining the proper mix ratios.

Glycol Feed System for Chiller Condenser Water Loop | Antifreeze Protection – Percentage Water to Temperature Ratio

Propylene Glycol% to Water

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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. It depends on the components in the loop, the application the chilled water system is supplying cold water for, and what the demand of the system requires for the chiller plant. Some chilled water valves control two-way valves while others control three-way valves. A three-way valve can either be a mixing valve or a diverting valve but the actuators controls the flow in either type of application. Other actuators modulate a valve based on demand. The actuator usually receives its command for position for control from the DDC system or another type of control system. In this case these actuators are controlled by DDC. In the sequence of operation the chiller plant will have a valve line-up usually in a valve matrix that was compiled by the original design engineer and this valve matrix shows the default position of the valves which are controlled by the actuators. Some applications in the piping that are controlled by the actuators include:

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Air Handler Water Coil Freeze Stat | Freezing Protection Control

Air Handler Water Coil Freeze Stat - Freezing Protection Control
Air Handler Water Coil Freeze Stat – The HVAC Air Handler Freeze Stat is a low temperature limit control and it is used mainly in commercial systems in the duct work on economizers or in air handlers just before any coil especially water coils. It is a safety and protection control to prevent extremely cold air from reaching the hot water or chilled water coils inside the air handler where the air enters from the economizer. Under ideal control set up if the freeze stat trips the economizer dampers close and the blower fan stops. This prevents coils from freezing. A frozen coil can bust open and will need to be replaced if it freezes thus the purpose of the freeze stat in HVAC air handler applications which utilize economizers for free cooling. (more…)

About Chilled Water Systems | HVAC Hydronics

About Chilled Water Systems | HVAC Hydronics

About Chilled Water Systems

About Chilled Water Systems

Old York Chiller

Chilled water systems are mainly used in large commercial HVAC air conditioning systems and industrial cooling applications although there are some residential and light commercial HVAC chilled water systems in use. Chilled water systems are popular because they use water as a refrigerant. Water is far less expensive than refrigerant. This makes them cost effective especially in commercial HVAC air conditioning applications. Instead of running refrigerant lines over a large area of the building water pipes are ran throughout the building and to evaporator coils in air handlers for HVAC air conditioning systems. The chilled water is pumped through these pipes from a chiller where the evaporator coil absorbs heat and returns it to the chiller to reject the heat.

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Chilled Water Pipe Vibration Isolators | HVAC Piping

Chilled Water Pipe Vibration IsolatorsChilled Water Pipe Vibration Isolators

Chilled Water Pipe Vibration Isolators – Vibration isolators protect the chilled water piping from receiving vibrations transmitted through the piping when the chillers are running. The vibrations can create problems not only for the chilled water piping but also for the buildings structure. The vibration isolators reduce or eliminate the vibrations that can be transmitted by the chillers. Other equipment normally specified with vibration isolators includes air handlers, pumps, condensing units, generators and most types of equipment with motors. Not only are vibration isolators required in the piping but vibration elimination springs or spring isolators are required are required on chillers, pumps, air handlers, and the other types of equipment named above which can produce vibrations when running. Vibration isolators are usually rated according to the static deflection the vibration isolator provides for the equipment. HVAC piping whether it is for hot water or chilled water usually is also specified with springs in the pipe hangers to avoid further issues that can be caused by vibration. Depending on the location vibration isolators will also be rated for seismic activity with further specifications calling for seismic restraints on the equipment and associated piping. (more…)

Ammonia Chilled Water System | Commercial HVAC

Ammonia Chilled Water SystemAmmonia Chilled Water System | Commercial HVAC

This chilled water unit is a new ammonia chiller. This unit is also unique in that it has no compressor. Instead it uses the chemical properties of ammonia and heat from natural gas to condense the refrigerant which is ammonia. A chiller provides chilled water to a chilled water loop. Cold water is circulated through a loop where it is direct into a coil in an air handler. Air is blown across a coil where a heat exchange process takes place. The air handler discharges cool conditioned air throughout a duct system. Chilled water systems are typically used in commercial air conditioning applicationsbut there are some chilled water systems in residential applications. (more…)

HVAC Definitions Terms & Acronyms | Heating Cooling

HVAC Definitions Terms & Acronyms | Heating Cooling – This is a comprehensive list of HVAC Acronyms and HVAC Terms. High Performance HVAC is certain there are more terms and acronyms. If you know of something we missed please email us. Thanks!

HVAC Definitions Terms & Acronyms

HVAC Definitions Terms & Acronyms - VSD or Variable Speed Drives

VSD or Variable Speed Drives

AC – Air Conditioning or Alternating Current

ACCA – Air Conditioning Contractors Associations

AFUE – Annual Fuel Utilization Efficiency

AHU – Air Handling Unit

AI – Analog Input

AMCA – Air Movement and Control Association

AO – Analog Output

AQS – Air Quality Systems

ASHRAE – American Society of Heating, Refrigerating, and Air Conditioning Engineers

AV – Automatic Air Vent

AWG – American Wire Gage

B – Boiler

BACnet – Computer communication protocol for building automation systems and control networks

BAS – Building Automation System

BI – Binary Input

BMS – Building Management System

BO – Binary Output

BP – Backflow Preventer

BTU – British Thermal Unit

BTUh – Brtish Thermal Units per Hour (more…)

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…)

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