Quiz 2 Flashcards
Define Heat Pump
-In cooling season, they absorb heat from conditioned space and reject it outdoors like a regular split system
-In heating season, they absorb heat from the cool outdoors and reject it into the conditioned space.
-Switch made possible by a reversing valve
Define Fan Powered Box (FPB)
-Similar to VAV box except it has an electric heat kit or hot water valve (HWV) and fan in it that allows it to heat the space it serves without using the main air handler for heating
-Series FPBs [aka Constant Volume Box (CVB)] provide continuous fixed airflow. Inefficient because the fan is runs continuously during occupancy and utilized plenum air.
-Parallel FPB uses primary air for cooling and only engages the fan to bring plenum air to be heated. Fan can turn off when heat is not needed.
Define Fan Coil Unit
-Generic term applied to a range of products
-Simple device consisting of a heating/cooling coil and a fan
-May have ductwork or discharge directly into the space
-Capable of providing outside are for cooling but usually do not
Define Cooling Tower
-Rejects building heat absorbed by the chiller in a chilled water system to the outdoors
Define Face and Bypass Dampers
-“Bypass” Portion: opens when control system needs to raise the temp of SA; directs air around cooling coil and sends it into the ductwork without going through the cooling coil.
-Remainder of the air passes through the “face” damper and through the cooling coil.
-The air streams mix in the ductwork going to the room raising the temp
-They are linked so when one opens the other closes
Define Supply Air
-SA - Heated or cooled air leaving the air handling unit that is delivered to the space by ductwork
Define Return Air-
-RA - Air being drawn from the space into the air handling unit.
-May be ducted or drawn through the open plenum formed by the ceiling tile and the floor of the next building floor
Define Outside Air
- OA - Drawn into the air handler by the suction of the fan
-Required by cod to provide ventilation of the space.
-Quantity of OA is defined by ASHRAE standards which are often adopted by local building codes.
-Traditionally 10-20% of SA volume in cubic feet per minute
Define Mixed Air
- Blend of RA and OA in the air handler. Temp and humidity of Mixed Air will depend on the percentages of this mixture.
Define CFM
-Cubic Feet per Minute: indicates a unit of volume of airflow in AC systems.
Define Ductwork
-Delivery system through which heated and conditioned air flows to and from the air handler and the space.
-May be flexible or sheet metal. Both will be insulated.
Define HVAC
-Heating Ventilation and Air Conditioning
-Encompasses the mechanical equipment and controls required to provide environmental comfort and acceptable indoor air quality in commercial and residential buildings.
Define Refrigerant
-Fluid used in refrigeration cycle that undergoes phase changes from a liquid to a gas and back again to absorb and reject heat from a space.
-Commonly referred to as “Freon” which is a registered trademark for a number of refrigerant products
Define Reversing Valve
-In a heat pump, it is responsible for sending the hot compressed gas from the compressor to either the outside condensing unit in the cooling mode, or to the indoor evaporator coil in the heating mode.
Define Damper
-Device that regulates the flow of air in a duct, VAV box or air handler
-May be operated by an automatic temperature control system using a damper motor or in some applications, manually.
Define JADE
-Programmable controller that is installed on units providing economizer control without an EMS
-Makes decisions based on the inputs it receives such as OA temp and space conditions.
-Makes the compressor the second stage of cooling when the OA settings are optimal for economizing or “free cooling”.
Define Point
-Most basic and most foundational element of computer programming logic in an EMS System
-Can be programmed through basic language programming or wiresheets.
-Inputs, outputs and variables
Define GUI
-Graphical Unit Interface - A program interface that takes advantage of the computer’s graphics capabilities to make the EMS easier to use.
-Frees the user from having to wade through complex programming languages by providing clickable graphics that display important info and allow you to navigate through the system.
Define Trend Log
-Monitoring tool in an EMS/Honeywell Contractor Pro that is either set up default in the system or can be set up by the user.
-Captures real time data about what is going on with certain points in an EMS/Honeywell Contractor Pro
-Time interval can be varied from as short as every minute tracking to 1 time during an hour
-Recommended 15 min intervals
Standard Chilled Water Supply Set Point
42º
What can trends be created for?
-Supply Air Temp
-Fan Status (on/off)
-Chilled Water Temps
-RA Temp
-Space Temp
-Relative Humidity
-Outside Air Temp
-AHU Status (on/off)
-Cooling and Heating Calls
