Hybrid heat pump for industrial applications: experimental characterization and optimal configuration

How to turn solar heat and industrial waste heat into useful cooling effect? Industrial processes are often energy-intensive and the need for their efficient decarbonization is now at the forefront of governmental and corporate policies worldwide. However, solutions for the green transition of the industrial sector should be:

  • Flexible
  • Widely applicable
  • Reliable

And should:

  • Minimize energy consumption
  • Reduce operational costs
  • Lower CO2 footprint

Is there a solution to all these answers? Heat pumps are the fit match to tackle these issues.

Within HYCOOL, CNR ITAE and Fahrenheit have developed a hybrid thermal heat pump for application in several industrial sectors where efficient and sustainable cooling is needed. But what is the hybrid heat pump?

The hybrid heat pump concept

HYCOOL system proposes the combination of a thermal heat pump with an electrical heat pump: the thermal heat pump exploits low-temperature waste heat (i.e. 70-90 °C) that is generally unused or dumped to the ambient. It can also be powered by renewable sources, such as solar heat and biomass. The electrical heat pump can exploit electricity locally produced (i.e. from PV panels or other sources) and thus further increase the share of renewables. The hybridization consists in the configuration of the two heat pumps: they can work in series, in parallel or in cascade by just changing the hydraulic connections. This makes HYCOOL configuration flexible and easily adaptable to different industrial cases.

In the framework of HYCOOL, two case studies are considered, which are shown in Figure 1:

  • At GIVAUDAN (chemical industry), process cooling at +5°C is needed. To achieve this target with an overall high efficiency, the base load is covered with an adsorption unit (80 kW nominal power) that cools down the fluid in the range 5-21°C. Peak load is supplied by a compression unit with a natural refrigerant (propane, R290), that is connected in series with adsorption unit.
  • At Bodedebò (food industry), cooling of food at -10°C is needed. In this case, the efficiency in cooling generation is achieved by using a cascade configuration: the thermal heat pump (adsorption) is used as topping stage for the electrical heat pump, in a two-stage system. This increases the efficiency of the electrical heat pump up to 40% at the expenses of renewable or even waste low-grade heat, so virtually without the need for extra cost.
Figure 1: HYCOOL flexible configuration of the hybrid heat pump.

Experimental evaluation of the hybrid heat pump

The hybrid heat pump was tested in the laboratories of CNR ITAE in Messina in design and off-design conditions (see Figure 2). The aim of the tests was to define the cooling power and electricity consumption of the hybrid heat pump in the different ambient and process operating conditions, as well as confirm the reliability under off-design conditions. To this purpose, more than 100 testing cases were evaluated, and the results were reported in form of performance maps, like those in Figure 3.

Figure 2: the hybrid heat pump installed at CNR.
Figure 3: performance maps of the hybrid heat pump tested at CNR.

Is HYCOOL solution feasible for you?

HYCOOL solution is widely suitable for a vast range of processes. To know whether solar cooling can be part of your industrial processes, a screening tool, based on process requirements and information on the solar radiation in your industry’s location, was realized and is accessible here:

The results of the experimental testing at CNR, instead, were used to compile a calculator to predict the refrigeration capacity and energy efficiency ratio (EER) of the cascade HYCOOL chiller for a given industrial cooling process. You can access the tool here:


Written by CNR-ITAE

How Much More Efficient Can Your Process Get?

HyCool’s technology helps industrial processes to achieve higher refrigeration efficiency by integrating solar heat with hybrid heat pump technology. The performance of a hybrid adsorption-compression cooling system mainly depends on the operation parameters of the process. We have developed a “Refrigeration Capacity and EER Calculator Tool” that helps you estimate the performance of hybrid heat pump technology based on hot water temperature, chilled water temperature, and dry cooler outlet temperature.

You can try it out! Click here!

D.3.4 Design review of the hybrid heat pump

Executive Summary

This document is the deliverable “D3.4 – Design review of the hybrid heat pump” in the European project “HYCOOL – Industrial Cooling through Hybrid system based on Solar Heat” (hereinafter also referred to as “HYCOOL”, project reference: 792073). HyCool Project Mission is increasing the current use of Solar Heat in Industry Processes, and to do so the project proposes the coupling of a new Fresnel CSP Solar thermal collectors (FCSP) system with specially build Hybrid Heat Pumps (HHP) (a “two in one” combination of adsorption and compressor-based heat pumps) for a wider output temperature range (Solar Heating & Cooling –SHC-), and a wide range of design and operational configurations to increase the potential implementation of the proposed Solar Heat in industrial environments. The solutions encompassed in the project will be implemented and tested in operational processes in two different pilot cases in the food and chemical industry. The food case pilot is hosted by Bo de Deb. which represents a small food industry in a high solar irradiation area with cooling needs in the production processes. Here the industrial cold installation is necessary for the good preservation of the product. The chemical case pilot targets industries with several processes in high solar irradiation areas with steam and cooling needs. This pilot is hosted by Givaudan where the cold installation makes use of a brine chiller to keep the water entering the liquid ring of the vacuum pumps at 7.C.

The purpose of this deliverable is to describe the key findings of the review process, which focuses on the design of the Hybrid Heat Pump. This report contains the findings with regard to control strategy, the interconnection of the heat pumps, selection of the suitable adsorbent and refrigerant, as well as an optimal size of the HHP.

D.3.3 Experimental characterization of the hybrid heat pump module

Executive Summary

This document is the Deliverable “D3.3 – Experimental characterization of the hybrid heat pump module ” of the European project “HYCOOL – Industrial Cooling through Hybrid system based on Solar Heat.” (hereinafter also referred to as “HYCOOL”, project reference: 792073).

This deliverable reports about the experimental performance evaluation of the hybrid cascading chiller under lab-controlled working conditions. The chiller was manufactured by Fahrenheit by connecting in cascade a silica-gel water adsorption cooling machine with a vapour compression chiller using R1270 (propylene) as refrigerant.

D.1.1 Interim first year report on project management

Executive Summary

The present deliverable D1.1 Interim first-year report on project management, hereafter named interim report (IR), contains the necessary information for the Hycool to evaluate the state of implementation of the project, mainly the work plan, the timely review of the scheduled milestones and deliverables will allow an efficient project implementation as well as concrete options for adjustments of management procedures, compliance with the provisions of the EC, finances, and monitors each partner’s costs, the financial situation of the project and all administrative matters. The technical part contains a concise statement of the tasks undertaken and a forecast for the next reporting period. Any problems encountered during the period and possible deviations from project plans. This deliverable set by the Consortium, is the first IR planed in the WP1 at M12, jointly with the other two IR planned at M18 and M36, at the end of the project. These deliverables are differentiated from the periodic reporting (PR) set by INEA and planned at M18 and M36. Basically, the PR includes the detailed description of the technical work carried out by beneficiaries, the work performed by the work package, the impact, and finally the deviations and the full financial information. This report covers the first period from M1 (May 2018) to M12 (April 2019).

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