AIRC 141 ASHRAE Hydronic Heating & Cooling System Design
* Hydronic Systems
* Convey heat/cool for processing – AHU
* Classified as –
* Operation temperature
* Flow generation
* Gravity systems
* Difference in density between supply and return water circuitry (ex. Radiant steam heating - old)
* Forced systems
* Pumping assisted
* Pressurization
* Piping arrangement
* Pumping arrangement
* Principles
* Complex relationships between various system components
* Design water temperature
* Flow rate
* Piping layout
* Pump selection
* Terminal unit selection
* Control methodology
* Present Hydronic heating system design
* Residential heating applications
* T of 11K(?) used to determine flow rate
* I think they meant 11F
* Makes more sense
* Water systems classified by operating temperature
* Low temperature water system (LTW)
* Max. 120C
* Medium temp. (MTW) water
* 120-175C
* High temp. (HTW) water
* >175C
* Chilled water (CW) systems
* 4 – 13C
* Usually 7C (44.6F)
* Closed water systems
* Defined as ‘one with no more than one point of interface with a compressible gas or surface, and that will not create system flow by changes in elevation’
* Differs from old existing definition – an open or vented expansion tank as an “open” system is actually a closed system – the atmospheric interface of the tank simply establishes the system pressure.
* Open system
* Has more than one such interface –
* Cooling tower has two interfaces
* Tower basin pressure
* Discharge pipe or nozzles entering the tower
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