HeatPumpControl

Control of trano's air-to-water heat pump (Buildings model): heating curve, heating season, buffer charged between TSupSet - dTHys/2 and TSupSet + dTHys/2, compressor PI on the condenser outlet towards TSupSet + dTHys (minimum speed yComMin); the minimum on and off times of the safety control are not modelled

FastSmoothBuildings.Controls.HeatPumpControl, model (source)

Purpose

Control of trano's air-to-water heat pump (Buildings model): a heating curve, a heating season, the charging of the buffer within a band and a PI controller of the compressor speed on the condenser outlet. The minimum on and off times of the safety control are not modelled.

Equations

Heating curve, linear in the outdoor temperature between the design point and the heating limit, bounded by smoothMin and smoothMax of width dT:

T_SupSet = smoothMin(T_Set, smoothMax(T_SupMin, T_Set + (T_SupMin − T_Set) (T_Out − T_OutDes)/(T_OutHeaLim − T_OutDes), dT), dT).

Two Hysteresis states and the filtered measurement:

• warOut: 1 (outside the heating season) when T_Out rises above T_OutHeaLim + 1 K, 0 when it falls below T_OutHeaLim − 1 K;
• bufCha: charging the buffer, from T_Buf < T_SupSet − dT_Hys/2 until T_Buf > T_SupSet + dT_Hys/2, charging at the start (y_start = 1);
• τ_Sen dT_Con/dt = T_ConOut − T_Con, T_Con(0) = T_Set.

Compressor:

heaOn = demand (1 − warOut.y) bufCha.y,   y = heaOn conCom.y,

conCom a PI controller of the error T_SupSet + dT_Hys − T_Con between yComMin and 1, enabled by heaOn and relaxed to yComMin while disabled. The compressor stops through the product with heaOn, whose factors are bistable states that switch within their time constants: the control has no event.

Parameters

Name	Default	Meaning
TSet	323.15 K	supply temperature at the design outdoor temperature
TSupMin	303.15 K	supply temperature at the heating limit
TOutDes	265.15 K	design outdoor temperature
TOutHeaLim	289.15 K	heating limit
dTHys	5 K	band of the buffer charging
kCom, TiCom	0.1, 300 s	gain and integral time of the compressor controller
yComMin	0.3	minimum compressor speed
tauSen	30 s	time constant of the condenser outlet temperature
dT	0.1 K	width of the smooth limits of the heating curve
dY	10−3 (1 − yComMin)	half-width of the smooth limits of the compressor speed

The hystereses keep their defaults (tau = 10 s, dU a tenth of their band: 0.2 K for warOut, dTHys/10 for bufCha), which modifiers such as bufCha.tau can change. With dT and dY, they are the smoothing that a calibration can widen.

Use

In Examples.HeatPumpCircuit, the demand from BoilerDemand.

Parameters

Parameter	Type	Unit	Default	Description
TSet	Real	K	323.15	Supply temperature at the design outdoor temperature
TSupMin	Real	K	303.15	Supply temperature at the heating limit
TOutDes	Real	K	265.15	Design outdoor temperature
TOutHeaLim	Real	K	289.15	Heating limit
dTHys	Real	K	5	Band of the buffer charging
kCom	Real		0.1	Gain of the compressor controller
TiCom	Real	s	300	Integral time of the compressor controller
yComMin	Real		0.3	Minimum compressor speed
tauSen	Real	s	30	Time constant of the condenser outlet temperature
dT	Real	K	0.1	Width of the smooth limits of the heating curve
dY	Real		1e-3*(1 - yComMin)	Width of the smooth limits of the compressor speed

Revisions

• October 2026: moved from trano's FastModel.Controls.