Frequency Inverters to save energy ASERCOM Association of European Refrigeration Component Manufacturers Annual Convention 2016 John P. Gibson ASERCOM WG Inverter Brussels, 14.01.2016
Participating in the ASERCOM Work Group Inverter Semi-hermetic Refrigerant Compressors: BITZER (D) DORIN (I) EMERSON Climate Technologies (B + CZ) FRASCOLD (I) GEA-BOCK (D) INGERSOLL-RAND (CZ) Hermetic Refrigerant Compressors BITZER (D) DANFOSS (DK) EMERSON Climate Technologies (CZ) TECUMSEH (F) Inverters for Refrigeration Technology BITZER (D) DANFOSS (DK) KIMO RHVAC (D) LODAM (DK) Compressor Monitoring KRIWAN (D) ASERCOM Convention, 14.01.2016 John Gibson 2
What is a Refrigeration Inverter? OR SAFE TORQUE OFF Voltage optimized for highest possible compressor efficiency 400 V 400 V 400 V 200 V 200 V 200 V 0 V 0 ms 10 ms 20 ms 30 ms 40 ms 0 V 0 ms 10 ms 20 ms 30 ms 40 ms 0 V 0 ms 10 ms 20 ms 30 ms 40 ms -200 V -200 V -200 V -400 V f: 25 Hz, 200 V 50 % capacity -400 V f: 50 Hz, 400 V 100 % capacity -400 V f: 70 Hz, 400 V 140 % capacity ASERCOM Convention, 14.01.2016 John Gibson 3
Some Energy Figures Electrical energy used for Refrigeration and Air Conditioning: 14% of total electrical energy consumption In Refrigeration and Air Conditioning Industrial: 14 % Domestic Data from the German Federal Environmental Agency Aircon: 15 % Retail: 8 % Food Industry: 9 % Supermarkets: 12 % Relevant for Frequency Inverters: 58 % ASERCOM Convention, 14.01.2016 John Gibson 4
Refrigeration Inverters for Indirect Cooling with a flammable refrigerant Cascade cooling of hop pellets for beer: LT (-40 C): R744 (CO 2 ) MT: R290 (Propane) Heat recovery Modernisation of existing plant: 50 % Energy saving measured 2015 / 2014 ASERCOM Convention, 14.01.2016 John Gibson 5
Refrigeration Inverters for high-efficiency cascade systems Large new Bakery: LT: R744 (CO 2 ), MT: R1234ze ASERCOM Convention, 14.01.2016 John Gibson 6
300 V 200 V 100 V 0 V 0 40 80 120 160 200 240-100 V -200 V -300 V Improving Compressor Operation and Control Decreasing Condensing temperature pc: One K ( C) decrease 1 2 % energy saving with (achievable, depends on annual Medium Temperature (-10 C) temperature profile) 0.5 1 % energy saving with Low Temperature (-35 C) (Source: Carbon Trust, UK) Increasing evaporation temperature pe: One K ( C) increase 2 4 % energy saving (achievable, depends on display-case design and operating conditions) Stable operating point pe: Inverter-Control provides for stable operation of expansion valve (achievable, depends on design) Actual energy saving figures under Work Group review (source: KÜBA Heat Exchangers) 10 20 % energy (source KIMO RHVACC) 45 C 30 C -6 C -10 C ASERCOM Convention, 14.01.2016 John Gibson 7
Experience with Inverter energy saving Thermodynamic targets: Condensing temperature Evaporating temperature Publication from KUBA evaporators: Energy saving with inverter compressor control (Experience assuming full advanced floating and optimized control of evaporating and condensing temperatures): 1x compressor: 30 40 % 2x compressor rack: 20 25 % 3x compressor rack: 17 22 % 4x compressor rack: 15 20 %, (At low capacity: 20 25 %) ASERCOM Convention, 14.01.2016 John Gibson 8
Achieving a stable compressor operating point with multi-compressor racks + + Step control without an inverter: Frequent STARTING and STOPPING (Too much or too little capacity) Large fluctuations in Evaporating Temperature: Little Energy Saving Poor-design inverter control: Unnecessary STARTING and STOPPING (instability at certain operating points) Fluctuations in Evaporating Temperature: Some Energy Saving Good-design inverter control: Minimum STARTING and STOPPING (stable operation due to wide range of speed): Optimum Energy Saving and Cooling Quality ASERCOM Convention, 14.01.2016 John Gibson 9
Importance of achieving a wide range of permissible operating frequency ASERCOM Convention, 14.01.2016 John Gibson 10
Benefit of a wide range of compressor frequency: Example with two-cylinder compressors Example for Identical-sized 2-cylinder compressors Control Factor CF = Capacity Variation of Inverter compressor Capacity of next step ASERCOM Convention, 14.01.2016 John Gibson 11
Benefit of a wide range of compressor frequency: Example with six-cylinder compressors Example for identical-sized 6-cylinder compressors Control Factor CF = Capacity Variation of Inverter compressor Capacity of next step ASERCOM Convention, 14.01.2016 John Gibson 12
Example of a real supermarket installation with a low Control Factor Shown here ASERCOM Convention, 14.01.2016 John Gibson 13
How can ASERCOM assist with using inverters in refrigeration? Provide design software for compressor manufacturers Mathematical basis for calculation of the electrical performance limits with frequency inverter operation : Maximum and minimum frequency at each refrigerant and operating point Performance projection, in particular the Coefficient Of Performance COP: COP COP = Refrigeration capacity_ COP Electrical consumption at all load conditions. ASERCOM Convention, 14.01.2016 John Gibson 14
How can ASERCOM assist with using inverters in refrigeration? Calculation Tool for compressor manufacturers Starting current Motor current Magnetic Field Operation up to 70 Hz often possible: - 40 % more capacity - Better control performance - Energy saving ASERCOM Convention, 14.01.2016 John Gibson 15
How can ASERCOM assist with using inverters in refrigeration? Issue Design Guides for the Refrigeration Industry: On the general use of Inverter with Refrigerant Compressors (2010) (published as an ASERCOM Guide Book on www.asercom.org) On the optimum design of Compressor Racks for high reliability and optimum Energy Saving (to be published soon as an ASERCOM Guide Book) NEW: Almost ready Others on electrical and Electromagnetic Compatibility (EMC) issues to follow. ASERCOM Convention, 14.01.2016 John Gibson 16
Using inverters to improve refrigeration cooling quality Constant evaporation temperature: Reduced temperature variations at the cooling outlets Higher and Constant Humidity Reduced weight loss by dehumidification Improved evaporator Operation: Improved function of the Expansion Valves: - Higher evaporator efficiency by optimum filling Less icing on the evaporators Longer intervals before each defrost : - Reduced energy loss during defrosting ASERCOM Convention, 14.01.2016 John Gibson 17
ASERCOM Convention, 14.01.2016 Christian Ellwein Control and Communication Proposal for a new ASERCOM WG
Why we need the new WG Trend 1: Energy Saving Energy saving potential is not only in optimizing a single component but optimization on a system level (refrigeration circuit, building automation ) Therefore communication between different components is necessary Trend 2: Security Many technical systems are not yet well designed for open networks like Internet. They are vulnerable to malware-attacks VDMA, VDE and governments have started to define standards like EMC or functional safety also for internet security Trend 3: Industry of Things / Industry 4.0 More and more machines, components and systems are expected to interact and communicate to: Improve maintenance Adapt to a new decentralized energy-world (German Energiewende ) with local suppliers and fluctuating energy providers (solar, wind ) Adapt to quickly changing demands ASERCOM Convention, 14.01.2016 Christian Ellwein
Possible Topics of the WG Basic communication protocol between components in the refrigeration circuit (e.g. compressor controller EEV), partly defined content, partly open to manufacturer specific content Risk analysis of a refrigeration circuit: which internet attacks could be possible? How to protect against those threads? Communication with systems outside the refrigeration circuit (building automation, factory automation): how to make Industry 4.0 happen for HVAC/R and communicate with e.g. Industrial Ethernet systems How to communicate with the electrical grid and energy providers to adapt to an decentralized grid? What are the effects on HVAC/R control strategies if the price of electricity is fluctuating much more and large energy consumers like HVAC/R might be disconnected or activated (to act as a energy storage ) for a certain time automatically? ASERCOM Convention, 14.01.2016 Christian John Gibson Ellwein 20
Using Frequency Inverters in Refrigeration, Summary Energy saving with Inverters for: Compressor racks Fans on condenser Circulation pumps for secondary cooling Improved Cooling quality: By good system design (ASERCOM explains how) ASERCOM Work Group inverter: 7x European Compressor manufacturers 4x European Inverter manufacturers 1x European Protection Equipment manufacturer Provide advice and Guide Books for the Refrigeration Industry.. ASERCOM Convention, 14.01.2016 John Gibson 21