©Fraunhofer ISE/Foto: Guido Kirsch

© Fraunhofer ISE FHG-SK: ISE-INTERNAL

R290 REFRIGERANT RESEARCHES AT FRAUNHOFER ISE

Low-GWP Refrigerant Workshop for IEA HPT's Annex 54: Heat Pumps for Low GWP Refrigerants

Lena Schnabel, Thore Oltersdorf, Simon Braungardt, Christian Sonner, Clemens Dankwerth, Timo Methler, Thomas Gindre, Peter Schossig

Fraunhofer Institute for Solar Energy Systems ISE

The 25th International Congress of Refrigeration

Montreal, Quebec, Canada | August 24-30

www.ise.fraunhofer.de

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AGENDA

Background and Motivation

R&D on natural refrigerants/ R290

planned ISE contribution to the Annex 54

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Background and Motivation Requirements of refrigerant

Efficiency, Sustainability, Energy Labelling

F-Gas-Regulation Safety, like EN 378

Requirements:

high efficiency, COP, heat capacity

attractive temperature range for domestic hot water/ heating/ industrial applications

low noise and vibrations

environmentally friendly -> low GWP, zero ODP

safe installation and operation

low installation and maintenance costs

design, user friendly, high degree of robustness …

Noise & Vibration

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Background and Motivation F-Gas-regulation

Focus on the phase down of the F-gases Requirements for 2030:

GWP < 490

Possible candidates

HFOs like R45x, R1234xx, ….

Natural refrigerant like NH3, CO2, HC’s, water

Risks

Flammable and explosive gases expect CO2 (>>pressure) and water (<<pressure)

Classes of A2L, B3 or A3

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R&D at Fraunhofer ISE on natural refrigerants/ R290 recent topics

Qualification and design of components

Compressor testing, oil management

Sizing of tubing system

Material selection

Refrigerant charge reduction

Optimized heat exchanger, fluid distribution, hydraulics

Oil management

Safety concepts for components and equipment

Noise analys is and reduction

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R&D at Fraunhofer ISE on natural refrigerants/ R290 qualification and design of components

TestLab with an area of 550 m²

Double climate chamber

Integral safety concept for flammable and toxic refrigerants

6 enclosed testing areas with gas detection and emergency ventilation

Set-ups for component testing (compressor, leakage, fluid distributor, heat transfer, sorption beds,…)

Voltage controller and stabiliser for most world grids

Versatile conditioning, measurement and analysis equipment

HiL, secure connection to partners

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R&D at Fraunhofer ISE on natural refrigerants/ R290 Refrigerant charge reduction

Refrigerant charge reduction adressed in the GreenHP project (EU grant agreement No 308816, 12/12-08/16)

Heat exchanger with small fluid channel dimensions

Reducing volume of distributors and tubing

Propane heat pump with compact heat exchanger and fractal distributor realized (GreenHP):

Charge reduction from based on new technologies and substituted refrigerant: 611g/kWHL to 76 g/kWHL (operation point A-7/W55, R-410A vs. propane)

Source: AIT/Ilgner

Source: ISE

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R&D at Fraunhofer ISE on natural refrigerants/ R290 Refrigerant charge reduction

Goal: 10kW using max. 150g R290

Reduction of inner volume

Compactness of unit

Confirmation of„Andersson 2018”

Identification of next steps

Areas of attention

Asymmetric Heat Exchangers

Compressor/ Amount of oil (unnecessary load?)

Pipe length

Unnecessary additional volumes

New design

LC150

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R&D at Fraunhofer ISE on natural refrigerants/ R290 Safety concepts for components and equipment

Leakage prevention

Identification of weak components/connections

Leakage detection

Quantification of detection methods (extrinsic & intrinsic)

Leakage control

Development and analysis of safety concepts

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R&D at Fraunhofer ISE on natural refrigerants/ R290 Safety concepts for components and equipment

Leakage prevention

Identification of weak components/connections in the refrigeration cycle (sight glasses, filter driers, material connections, solder connections, flanges, screw connections, valves etc.)

Investigation of the stability by thermal/mechanical cycling of the test objects

Refrigerants: Propane and Propylene

3000 cycles per day

Simulation of the operating time (defrosting processes)

Temperature cycles: -10°C to 70°C

Pressure cycles: 4bar to 18bar

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R&D at Fraunhofer ISE on natural refrigerants/ R290 Safety concepts for components and equipment

Leakage prevention

Identification of weak components/connections

Leakage detection

Quantification of detection methods (extrinsic & intrinsic)

Leakage control

Development and analyze of safety concepts

Capturing refrigerants using sorption materials

Support of risk assessment (LOPA, ETFA)

Evaluation at outdoor test field

Source: ISE

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planned ISE contribution to the Annex 54 natural refrigerants and charge reduction

review on comparative evaluations between systems using A2L/ A3/ traditional refrigerants (with focus on R134a, R404A, R407C, R410A). (input for Task 1/ Annex 54)

experimental study of different refrigerants applied in the same heat pump device (probably R410A compared with R290, R32 and one addititional A2L refrigerant) (input for Task 1/ Annex 54)

Modification of the heat pump with respect to refrigerant charge reduction down to 500 g, if possible use of an air-based evaporator. (input for Task 1/ Annex 54)

support of normative work with focus on risk analysis and leckage detection

Input on water used as refrigerant will be additionally possible (national project started in 06/19)

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Thank you for your Attention!

Fraunhofer Institute for Solar Energy Systems ISE

Dr. Lena Schnabel

www.ise.fraunhofer.de

lena.schnabel@ise.fraunhofer.de