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Dev:Commercial - Commercial building developer's guide


Note 
The small office building is part of the original implementation of the commercial module and is expected to be deprecated when the full commercial building implementation is completed. This will include deprecation of the multizone class. Small office buildings will be derived from the building implementation when that is validated and released.

Building

The building class implements that abstract class used to solve all linearized multizone building models. All multizone commercial building classes are derived from this class.

Class members


General properties
Property
Unit
Constraints
Default
Description
Remarks
T degF N×1 ∈ R Ø Node temperatures
N (int16) N+ 1 Number of nodes in model
U Btu/degF/h N×N symmetric ∈ R*2 Ø Node conductances
C Btu/degF N×1 ∈ R* Ø Node capacitance NaN indicates outdoor node
Q Btu/h N×1 ∈ R Ø Node heat flows
Qs Btu/h N×1 ∈ R* Ø Node solar heat gain
Qi Btu/h N×1 ∈ R* Ø Node internal heat gain

Default HVAC properties
Property
Unit
Constraints
Default
Description
Remarks
Qfl Btu/h N×1 ∈ R* NaN Node fan heat gain at low power
Qfh Btu/h N×1 ∈ R* NaN Node fan heat gain at high power
Qf Btu/h N×1 ∈ R* NaN Node heat gain from fans
Qhc Btu/h N×1 ∈ R* NaN Node heating capacity
Qh Btu/h N×1 ∈ R* NaN Node heat gain from heating
Qcc Btu/h N×1 ∈ R* NaN Node cooling capacity
Qc Btu/h N×1 ∈ R* NaN Node heat loss from cooling
Note : NaN is used to indicate that no default HVAC equipment is associated with the node

Default controller properties
Property
Unit
Constraints
Default
Description
Remarks
Ts (double) N×1 ∈ {0,1,2,3,4,5} NaN HVAC state 0=OFF, 1=VENT, 2=HEAT, 3=COOL, 4=AUX, 5=ECON
Vm pu/h N×1 ∈ R* NaN Minimum ventilation required
Th degF N×1 ∈ R+ NaN Heating set-point Must be less than [math]Tc-2Td[/math]
Tc degF N×1 ∈ R+ NaN Cooling set-point Must be greater than [math]Th+2Td[/math]
Td degF N×1 ∈ R+ NaN Set-point deadband
tl s N×1 ∈ N+ 300 Control lockout time Must be less than or equal to maximum_timestep
Note : NaN is used to indicate that no default control equipment is associated with the node

Other members
autosize (bool) ∈ {TRUE,FALSE} FALSE Enables automatic sizing of arrays
load (enduse) Electric end use load composition

Default HVAC Controller

The default controller implements a simple single zone vent/heat/cool/aux control. To override the default controller you must implement the plc() function is the derived class.

The default control strategy for node n is as follows:

if mode == OFF || mode == VENT
  if T < Th-2*Td
    mode = AUX
  else if T < Th - Td/2
    mode = HEAT
  else if T > Tc + Td/2
    mode = COOL
  else if Vm > 0 
    mode = VENT
  else
    mode = OFF

else if mode == HEAT
  if T < Th-2*Td
    mode = AUX
  else if T > Th+Td/2
    if Vm > 0
      mode = VENT
    else
      mode = OFF

else if mode == COOL
  if T < Tc - Td/2
    if Vm > 0
      mode = VENT
    else
      mode = OFF

else if mode == AUX
  if T > Th - Td/2
    if Vm > 0
      mode = VENT
    else
      mode = OFF
Note 
Implementing the plc() function for a building means that the default controller is disabled for all nodes in the building. This means that if you want to continue using the default controller for some nodes you must call the building::plc() function directly for that node.

See also