Hydronics

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

  * Fundamental...