[autonomous]

So I managed to run a few example simulations included with EnergyPlus for a radiant hydronic heating system. It generates a ton of data, but I was looking for something that described the flow characteristics of the system which would eventually be implemented in a physical system.

Code: Select all

! RadLoTempHydrCoolTower.idf
!
! Basic file description:  1 story building divided into 3 interior conditioned zones. Roof with no plenum.
!                          No ground contact with floor.
!
! Highlights:              Hydronic low temperature radiant system heats and cools
!                          "Chilled" water provided only by a cooling tower
!
! Simulation Location/Run: CHICAGO_IL_USA_WMO_725300, 2 design days, 1 run period,
!                          Run Control executes the design days only.
!
! Location:                Chicago, IL
!
! Design Days:             CHICAGO_IL_USA Annual Heating 99%, MaxDB=-17.3°C
!                          CHICAGO_IL_USA Annual Cooling DRY (DB=>MWB) 1%, MaxDB=31.5°C MWB=10°C
!
! Run Period (Weather File): none
!
! Run Control:             No Zone or System sizing required (design days only, see RUN CONTROL object)
!
! Building: Single floor rectangular L-shaped building 40 ft south wall, 40 ft west wall, zone height 10 feet.
!           There is a single window in the West Zone south wall. The walls are 1 in stucco over 4 in common brick
!           and gypboard. The roof is a built up roof with 1/2 in stone over 3/8 in felt over 1 in dense insulation
!           supported by 2 in heavy weight concrete. The window is single pane 3mm clear.
!           The window to wall ratio is approxomately 0.07.
!
!           The building is oriented due north.
!
! Floor Area:        130.1 m2 (1403 ft2)
! Number of Stories: 1
!
! Zone Description Details:
!
!       (0,12.192,0)                 (9.144,12.192,0)
!           ________________________________
!          |                                |
!          |                                |
!          |                                |
!          |                                |
!          |           North                |
!          |                                |
!          |                                |
!          |             (6.096,6.096,0)    |
!          |________________________________|____________ (12.192,6.069,0)
!          | (0,6.096,0)        |    (9.144,6.096,0)     |
!          |                    |                        |
!          |                    |                        |
!          |                    |                        |
!          |       West         |         East           |    window = *
!          |                    |                        |
!          |                    |                        |
!          |                    |                        |
!          |___**************___|________________________|
!
!      (0,0,0)             (6.069,0,0)               (12.192,0,0)

Report: Component Sizing Summary
================================
For: Entire Facility
Timestamp: 2012-12-29 21:38:18

ZoneHVAC:LowTemperatureRadiant:VariableFlow

Maximum Hot Water Flow [m3/s]   Maximum Cold Water Flow [m3/s]   Hydronic Tubing Length [m]
WEST ZONE RADIANT FLOOR    0.000139    0.000603    247.74
EAST ZONE RADIANT FLOOR    0.000142    0.000544    247.74
NORTH ZONE RADIANT FLOOR    0.000205    0.000735    371.61

PlantLoop

Maximum Loop Flow Rate [m3/s]   Plant Loop Volume [m3]
CHILLED WATER LOOP    0.001881    1.41
HOT WATER LOOP    0.000486    0.364602

Pump:VariableSpeed

Rated Flow Rate [m3/s]   Rated Power Consumption [W]
CIRC PUMP    0.001881    480.69
HW CIRC PUMP    0.000486    124.20

Report: Adaptive Comfort Summary
================================
For: Entire Facility

Timestamp: 2012-12-29 21:38:18

Time Not Meeting the Adaptive Comfort Models during Occupied Hours

ASHRAE55 90% Acceptability Limits [Hours]   ASHRAE55 80% Acceptability Limits [Hours]   CEN15251 Category I Acceptability Limits [Hours]   CEN15251 Category II Acceptability Limits [Hours]   CEN15251 Category III Acceptability Limits [Hours]




[Pops]

So I fiddled around with a couple of dumb thermostats yesterday to see how far I could get... (use the scroll bar, there are 4 drawings...

2 Zone Schematic.jpg

Obviously the thing that is different than just a typical 2 zone hydronic system is "zone 1" sometimes acts as a heat "source" for the other, shaded, zone 2, which acts like storage.

Using programable t-stats would do some anticipating and extending the delay to avoid short cycling, not as well as logic and more inputs (outside temp, season, day length, etc) but certainly simpler in the short run and very farmiliar to an inspector.

I'm still figuring a cooling cycle, I have the cooling leg of T-stat #2 left!


Lots of control, plumbing & radiant stuff here:
http://www.houseneeds.com/default.asp