Dataset of Experimental Optimisation of the Performance of a High‑Temperature Heat Pump Under Part‑Load Conditions

This dataset contains comprehensive experimental measurements of a high‑temperature heat pump (HTHP) operating under part‑load and off‑design conditions, as well as the experimental optimisation of the part‑load performance. The data were acquired on a laboratory-scale test rig developed at the Chair of Engineering Thermodynamics and Transport Processes (LTTT) at the University of Bayreuth. The experiments investigate the thermodynamic behaviour, efficiency characteristics, and optimisation potential of an HTHP using the low‑GWP refrigerant R1233zd(E).

The test rig represents a 37 kW single‑stage vapour compression cycle equipped with:

A semi-hermetic reciprocating compressor
An internal heat exchanger (IHX) with a controllable bypass
A plate evaporator and condenser operated in counterflow configuration
Water-cooled cylinder heads (CHC)
Software-controlled secondary circuits for heat source and heat sink conditioning
Full PID-based control for superheat, flow rates, and temperature stabilisation
The working fluid R1233zd(E)
A flowchart is attached in the files.

The dataset covers several structured experimental campaigns, including:

1. Part‑Load Operation
Compressor speed: 750–2100 rpm (25–70 Hz)
Boundary conditions (“base scenario”):
Heat source inlet: 60 °C, ΔT = 10 K
Heat sink outlet: 120 °C, ΔT = 60 K

For each speed, measurements include variations of:
Evaporator superheat (SHevap)
Suction gas superheat via IHX bypass (SHsuc)

2. Off‑Design Operation
At constant compressor speed (1517 rpm), the following were varied:
Heat sink outlet temperature: 75–140 °C
Evaporator temperature difference: 7–15 K
Condenser temperature difference: 10–70 K

3. Optimised Part‑Load Operation
Compressor speed: 750–2100 rpm (25–70 Hz)
Boundary conditions:
Heat source inlet: 60 °C, ΔT = 10 K
Heat sink outlet: 120 °C, ΔT = 60 K

Variation of cylinder head cooling, superheating after the evaporator, and variation of the recuperated thermal energy in the IHX.
These experiments characterise the system’s behaviour under fluctuating industrial boundary conditions.

The dataset contains high‑resolution measurements (steady-state, 10‑min stability criteria):
Pressures at all state points (PIR) in bar
Temperatures at all state points (TIR) in °C
Mass flow rates or volumetric flow rates in all circuits (FIR) in l/h; except FIR1_05 in g/s
Electrical compressor power (Pel) in kW
Control valve positions (expansion valve (EAV), IHX bypass)
COP
Thermal capacity source QWQ in kW
Thermal capacity sink QWS in kW
Frequency f in Hz

This dataset enables heat pump modelling, validation of numerical simulations, analysis of compressor behaviour under part‑load and off‑design conditions, and the development of advanced control strategies. It further supports research on industrial integration of high‑temperature heat pumps, utilisation of waste heat, assessment of low‑GWP working fluids, and system‑level optimisation.