The operating concept
- 01
Process-fluid circuit
The 25–30% propylene-glycol process fluid passes through HX1, transferring process heat into the power circuit.
- 02
HX1 captures heat
In HX1, R-1224yd(Z) absorbs heat from the glycol circuit and leaves toward the booster compressor.
- 03
Booster compression
The booster screw compressor raises the refrigerant pressure and temperature before it enters the expander.
- 04
Expander + PMG
A reverse screw compressor acts as the expander and drives a permanent-magnet generator as the refrigerant expands.
- 05
HX2 transfers heat
HX2 condenses the power-circuit refrigerant while transferring useful heat into the separate R-1224yd(Z) circuit.
- 06
EEV closes the power loop
The electronic expansion valve meters the condensed refrigerant, reduces its pressure, and returns it to HX1.
- 07
Pumped heat-output circuit
A pump circulates the second R-1224yd(Z) circuit from HX2 through a fan coil or optional hot-water recovery exchanger and back to HX2.
- 08
Dedicated oil circuit
A separate POE oil circuit with reservoir, pumps, filtration, pressure control, and oil cooling supports the booster compressor and expander.
Power circuitHX1 → booster compressor → expander / PMG → HX2 → EEV → HX1
Heat-output circuitHX2 → fan coil / hot-water recovery → pump → HX2
Process-fluid circuitProcess return → HX1 → cooled process supply
Oil circuitReservoir → pumps / conditioning → booster + expander → reservoir
Energy sourceNormally rejected chiller heat
Electrical outputReverse screw expander + PMG + grid-tied inverter
System benefitLower net demand + useful heat recovery
Grid connectionSite-load offset + approved power export
Concept specifications
- Architecture
- Four coordinated circuits: power refrigerant, heat-output refrigerant, POE oil, and process fluid
- Cooling capacity target
- Approx. 488,000 BTU/h
- Equivalent cooling capacity
- Approx. 40.7 refrigeration tons / 143.0 kW thermal
- Preliminary process flow
- 70 GPM — 25–30% propylene-glycol circuit
- Preliminary process temperatures
- 45°F entering / 32°F leaving (13°F drop)
- Working refrigerant
- R-1224yd(Z) in both refrigerant circuits
- Refrigerant environmental profile
- Very low GWP (~1) · A1 safety classification
- Heat-output circuit flow
- 35 GPM — pumped R-1224yd(Z) circuit
- Dedicated oil-circuit flow
- Approx. 1.5–2.5 GPM — POE oil
- Concept model
- ThermaVoltHx-30
- U.S. electrical service
- 120/208 V, 3-phase or 277/480 V, 3-phase · 60 Hz
- HX-30 auxiliary draw
- 12.2 kW
- HX-30 generation target
- 30 kW
- Optional hot-water recovery target
- Approx. 388,000 BTU/h useful heat output
- Recovered energy source
- Normally rejected chiller heat
- Intended result
- Electricity generation + useful heat recovery + reduced net demand
- Generation equipment
- Reverse screw expander, PMG and grid-tied inverter
- Grid interface
- Site-load offset with potential utility-approved power export
- Control concept
- Local fast loops + supervisory web controls
- Protection concept
- Pressure, temperature, isolation and fail-safe interlocks
ThermaVoltHx is a development-stage concept. The approximate 488,000 BTU/h process-cooling and 388,000 BTU/h optional hot-water-recovery figures are preliminary design targets from the final concept drawing, not tested ratings. Actual performance depends on fluid properties, flow, temperatures, component selection, and operating conditions. Cooling capacity and recovered heat are thermal duties, not electrical output. All four circuits, R-1224yd(Z) selection, ratings, electrical interface, grid interconnection, approvals, net power reduction, and overall performance must be confirmed through prototype testing and project-specific validation. Cooling, heat-recovery, and generation targets are not guaranteed commercial ratings; power export depends on the inverter, local utility rules, an approved interconnection agreement, and any applicable metering or export program.