Buildings.Templates.Plants.Controls.PolyvalentHeatPumps

Information

This package contains subsequences that are specific to polyvalent heat pump controls.

Package Content

Name	Description
AssertMinimumRuntime	Assert that polyvalent heat pumps are not short cycling
ExtractStagingMatrix	Extract staging matrix at current stage index of opposite operating mode
ModeAlternation	SHC and single mode alternation
StagingParameters
Validation

Buildings.Templates.Plants.Controls.PolyvalentHeatPumps.AssertMinimumRuntime

Assert that polyvalent heat pumps are not short cycling

Information

This block asserts that each polyvalent heat pump does not short cycle, based on its heating and cooling on/off commands.

If use_runTim=true (default), it asserts that each mode command remains true for at least dt_min before it turns false.

If use_runTim=false, it asserts that each mode command remains false for at least dt_min before it turns true.

Parameters

Connectors

Modelica definition

Buildings.Templates.Plants.Controls.PolyvalentHeatPumps.ExtractStagingMatrix

Extract staging matrix at current stage index of opposite operating mode

Information

Given the pre-computed staging matrix sta (either staCoo or staHea from Buildings.Templates.Plants.Controls.PolyvalentHeatPumps.StagingParameters) and the current stage index u of the opposite operating mode, this block extracts the corresponding n_Sta × n_Equ slice of normalized equipment fractions for all non-zero stages of the primary mode.

The number of stages n_Sta is recovered from the row count n_Row = (n_Sta + 1) ⋅ n_Sta by solving the resulting quadratic:

n_Sta = ⌊(1 + √(1 + 4 ⋅ n_Row)) / 2⌋ - 1

n_Equ equals the number of columns.

The output matrix corresponds to that specified in the documentation of Buildings.Templates.Plants.Controls.StagingRotation.EquipmentEnable and can therefore be consumed by this block.

If is_transpose = true, the block outputs the transpose of the staging matrix, with dimensions n_Equ × n_Sta.

Parameters

Connectors

Modelica definition

Buildings.Templates.Plants.Controls.PolyvalentHeatPumps.ModeAlternation

SHC and single mode alternation

Information

Heating-only

When a stage transition yields a change in both the number of staged units in heating mode and the number of staged units in SHC mode, i.e., a unit switches from/to heating-only to/from SHC mode: the units previously enabled in cooling mode are removed from the staging order for the heating enable logic. The heating enable logic can thus disable a unit previously enabled in either heating or SHC mode, or enable a unit previously enabled in SHC mode or disabled.

At any other time, the units previously enabled in cooling or SHC mode are removed from the staging order for the heating enable logic. The heating enable logic can thus only disable a unit previously enabled in heating mode, or enable a unit previously disabled.

Cooling-only

When a stage transition yields a change in both the number of staged units in cooling mode and the number of staged units in SHC mode, i.e., a unit switches from/to cooling-only to/from SHC mode: the units previously enabled in heating mode are removed from the staging order for the cooling enable logic. The cooling enable logic can thus disable a unit previously enabled in either cooling or SHC mode, or enable a unit previously enabled in SHC mode or disabled.

At any other time, the units previously enabled in heating or SHC mode are removed from the staging order for the cooling enable logic. The cooling enable logic can thus only disable a unit previously enabled in cooling mode, or enable a unit previously disabled.

SHC

At any time, the units currently enabled in heating or cooling mode are removed from the staging order for the SHC enable logic. The SHC enable logic can thus only disable a unit enabled in SHC mode, or enable a disabled unit. It cannot disable a unit that has been enabled in heating or cooling mode.

Details

Staging logic requirement

The alternation logic in this block assumes that stage transitions are elementary in terms of staged unit counts: either the number of staged units changes by one in exactly one operating mode – a unit is staged on or off – or the number of staged units decreases by one in one operating mode and increases by one in another operating mode – a mode switch at plant level, which the enable logics may realize with two distinct units. The staging logic shall preclude any other transition. Under this assumption, a simultaneous change in the number of staged units in a single mode and in SHC mode identifies without ambiguity a mode switch between that mode and SHC mode.

Resolution order

The heating and cooling enable logics resolve against the unit assignment prior to the stage transition, whereas the SHC enable logic resolves against the resulting heating and cooling enable commands. This establishes the resolution order between the three logics: at a transition where a unit switches between a single mode and SHC mode, the unit claimed by the heating or cooling enable logic is removed from the staging order for the SHC enable logic at the same time instant.

Note that a unit switching from SHC mode to a single mode, or conversely, is not subject to the minimum off-time required by Buildings.Templates.Plants.Controls.HeatPumps.Subsequences.EquipmentAvailability for the alternation between heating-only and cooling-only mode.

Parameters

Connectors

Modelica definition

Buildings.Templates.Plants.Controls.PolyvalentHeatPumps.StagingParameters

Information

This block pre-computes all staging parameters for a plant with n_HP standard reversible heat pumps and n_PHP polyvalent heat pumps (capable of simultaneous heating and cooling, SHC).

Fundamental assumptions

Within each equipment set (reversible HPs and polyvalent HPs), all units are assumed to be equally sized and are treated as lead/lag alternates. Adding one unit of either type therefore contributes one additional stage of capacity, so the maximum number of plant stages is n_Sta = n_HP + n_PHP. Heating and cooling stages are tracked independently, each ranging over {0, …, n_Sta}, since the same pool of units can serve either load.

For each combination of active heating and cooling stages (i_Hea, i_Coo) with i_Hea, i_Coo ∈ {0, …, n_Sta}, the block resolves how many units operate in each mode by applying the following assignment rules in order.

1. SHC assignment

Polyvalent HPs are assigned to simultaneous heating and cooling first, saturating at the available count and at the smaller of the two stage indices (since each SHC unit satisfies one heating stage and one cooling stage simultaneously):

n^SHC_PHP = min(min(i_Hea, i_Coo), n_PHP)

The residual heating and cooling stages after SHC assignment are:

i^res_Hea = i_Hea - n^SHC_PHP,    i^res_Coo = i_Coo - n^SHC_PHP

2. Heating assignment

Standard HPs cover the residual heating stage first:

n^Hea_HP = min(i^res_Hea, n_HP)

Any remaining residual heating stage is covered by polyvalent HPs operating in heating-only mode (drawn from those not already in SHC):

n^Hea_PHP = min(i^res_Hea - n^Hea_HP,  n_PHP - n^SHC_PHP)

3. Cooling assignment

Standard HPs not used for heating are assigned to the residual cooling stage:

n^Coo_HP = min(i^res_Coo,  n_HP - n^Hea_HP)

Remaining polyvalent HPs (neither in SHC nor heating-only) cover any unmet cooling stage:

n^Coo_PHP = min(i^res_Coo - n^Coo_HP,  n_PHP - n^SHC_PHP - n^Hea_PHP)

Feasibility

A stage combination is feasible if and only if both residual stages are fully covered by the assigned units:

i^res_Hea = n^Hea_HP + n^Hea_PHP    and    i^res_Coo = n^Coo_HP + n^Coo_PHP

Combinations that cannot be satisfied with the available equipment (e.g., requiring more simultaneous heating and cooling stages than there are polyvalent HPs) are flagged in is_feasible and receive zero weights in the staging matrices.

Staging matrices

The parameters staCoo and staHea pack feasible stage combinations into matrices consumed by the equipment enable logic. Each has (n_Sta + 1) × n_Sta rows (one per non-zero stage transition) and n_HP + 2 n_PHP columns, ordered as: standard HPs | polyvalent HPs (cooling- or heating-only) | polyvalent HPs (SHC).

For staCoo, row r corresponds to i_Hea = ⌊(r - 1) / n_Sta⌋ (outer index, 0 ≤ i_Hea ≤ n_Sta) and i_Coo = (r - 1) mod n_Sta + 1 (inner index, 1 ≤ i_Coo ≤ n_Sta). Column values are normalized fractions, as specified in the documentation of Buildings.Templates.Plants.Controls.StagingRotation.EquipmentEnable.:

• Columns 1 … n_HP:  n^Coo_HP / max(n_HP, 1)
• Columns n_HP + 1 … n_HP + n_PHP:  n^Coo_PHP / max(n_PHP, 1)
• Columns n_HP + n_PHP + 1 … n_HP + 2 n_PHP:  n^SHC_PHP / max(n_PHP, 1)

A row of zeros indicates an infeasible stage combination. staHea follows the same column layout but with i_Coo as the outer index and i_Hea as the inner index, and the heating counts substituted for the cooling counts.

Parameters

Modelica definition