Green economy with natural refrigerants

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Samson Long
5 years ago
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2 Green economy with natural refrigerants by

3 Heating, Cooling and Defrosting Flexible refrigeration with secondary systems Logistic center in Germany shows the indirect way to the future By Roger Rosander, Product Manager, Temper Technology AB Stina Olausson, General Manager, Temper Technology AB

4 Agenda Secondary refrigeration systems Wishes for Heat Transfer Fluid - HTF Different types of HTF Installation and maintenance for secondary refrigeration systems Heat transfer properties Waste heat defrost Logistic centre with heating, cooling and defrosting Logistic centre Review Questions Schaffhausen, 28 June 2013 Page 4

5 Secondary Refrigeration Systems Why using Heat Transfer Fluids, HTF, and secondary systems Low pressure lower risk Easier installation and easier maintenance Smaller refrigerant fillings High performance natural refrigerants, such as ammonia and hydrocarbons, may be used Equipment in contact with the refrigerant is confined to the machinery room Secondary fluid can be used for waste heat defrost Schaffhausen, 28 June 2013 Page 5

6 Wishes for HTF High specific heat enables that great cooling power can be transferred at small temperature change High thermal conductivity allows good heat transfer and thus small temperature difference in heat exchangers Low viscosity which gives low pressure drop and thus smaller pumps and small pump power Cheap Safe to handle Non toxic Not flammable No or low impact to the environment Low freezing point Schaffhausen, 28 June 2013 Page 6

7 Different types of HTF Glycols most common, widely used and generally known MEG toxic MPG low toxic, high viscosity at low temperatures Alcohols mostly used in heat pumps, flammable, high viscosity at low temperatures Inorganic salts commonly used in ice rinks Calcium chloride corrosive, high efficiency Organic salts low freezing point, high efficiency Potassium salts some material restrictions (galvanized steel) Ammonia high efficiency, high ph (corrosive), material restrictions (copper) Schaffhausen, 28 June 2013 Page 7

8 Installation and maintenance for secondary refrigeration systems Summary Material choices of piping, pumps, valves etc. Packing material Connection methods (in priority order) 1. Welding 2. Brazing 3. Flange joints 4. Threaded joints Clean system before filling Air purge carefully when start-up and continuously during operation Install filter Regularly check-up of the HTF Schaffhausen, 28 June 2013 Page 8

9 Heat transfer properties Thermal properties a comparison Basic conditions: Operation temperature: -10 C Tube diameter: 0,016 m Flow velocity: 1 m/s Freezing point : -20 C Product Density kg/m 3 Specific heat kj/kg K Thermal conductivity W/m K Dynamic viscosity mpas Kinematic viscosity mm 2 /s Re Reynolds number Pressure drop kpa Heat transfer coefficient W/m 2 K Organic salt (Temper-20) Calcium chloride Ethanol, 30% Propylene glycol 40% Ammonia, 14% ,233 0,467 5,14 4, , ,985 0,529 4,50 3, , ,162 0,394 11,67 12, , ,735 0,385 20,89 20, , ,241 0,459 2,75 2, , Schaffhausen, 28 June 2013 Page 9

10 Heat transfer properties Thermal properties in reality Thermowave Plate heat exchanger 1 MW (-12 o C/-18 o C) Organic salt (Temper-40) Propylene glycol (50%) Flowrate (m 3 /h) Pressure drop (kpa) Surface (m 2 ) (+47,8%) Weight (kg) Price per heat exchanger 100 % % Schaffhausen, 28 June 2013 Page 10

11 Heat transfer properties Thermal properties in reality Comparison - Pump for HTF circuit HTF - Temperatur (-18 o C) Pump manufacturer Organic salt (Temper-40) Wilo IL 150/190-5,5/4 Propylene glycol (50%) Wilo IL 150/220-11/4 Pressure height (m) 5,81 10,04 Electr. power (kw) 5,75 10,1 (+76%) Energy kwh (8000 h) Price pumps 100 % 120 % Schaffhausen, 28 June 2013 Page 11

12 Waste heat defrost Defrost may be achieved in different ways, electrical or by using warm brine. Electrical defrost high quality energy is consumed Waste Heat Defrost condenser heat or waste heat is used - Same warm HTF as cooling HTF - Warm HTF different than the cooling media (double piping) Advantages with Waste Heat Defrost Use of waste heat Shortening of time for each defrosting Fewer defrost cycles, i.e. melting instead of evaporating resulting in moist Even temperatures better food quality SQD = 3-way valve arrangement Schaffhausen, 28 June 2013 Page 12

13 Waste heat defrost Double piping coolers from wellknown manufacturers Temper / CO 2 Schaffhausen, 28 June 2013 Page 13

14 Waste heat defrost CO 2 secondary refrigerant pipes Temper defrost pipes Schaffhausen, 28 June 2013 Page 14

Logistic centre with Heating, Cooling and Defrosting Heating, cooling and defrosting is integrated with a secondary system Customer demands Use of natural

15 Logistic centre with Heating, Cooling and Defrosting Heating, cooling and defrosting is integrated with a secondary system Customer demands Use of natural refrigerants High performance/efficiency Low energy consumption Refrigeration systems with complete heat recovery Environmental aspects Schaffhausen, 28 June 2013 Page 15

16 Logistic centre with Heating, Cooling and Defrosting Schaffhausen, 28 June 2013 Page 16

Logistic centre with Heating, Cooling and Defrosting Self-supporting plant in terms of heating/cooling Capacities: Capacity Temper -6/-2 C: 500kW to 3654kW Capacitiy CO2-24 C: 190kW to 2000kW Heat

17 Logistic centre with Heating, Cooling and Defrosting Self-supporting plant in terms of heating/cooling Capacities: Capacity Temper -6/-2 C: 500kW to 3654kW Capacitiy CO2-24 C: 190kW to 2000kW Heat recovery +35/+25 C: 800kW to 1900kW Defrost Capacitiy MT Temper -15 C: 120kW to 550kW Defrost Capacitiy LT / CO2 Temper -40: 120 to 550kW Also heating capacity (fruits and vegetables) Temper -15: 200kW Schaffhausen, 28 June 2013 Page 17

18 Logistic centre Cold rooms Schaffhausen, 28 June 2013 Page 18

19 Logistic centre CO 2 freezer room with Temper -40 defrosting Schaffhausen, 28 June 2013 Page 19

20 Logistic centre Freezer room -24 C Froster with transport boxes -30 C Schaffhausen, 28 June 2013 Page 20

21 Logistic centre Outside condenser Ammonia compressor Ammonia heat pump Schaffhausen, 28 June 2013 Page 21

22 Review In a refrigeration plant waste heat is inevitable. By recovering the waste heat the premises are fully self-supported. Recovering is done by: Defrosting medium temperature Defrosting low temperature Floor heating Hot water production via HP Heating of fruit and vegetables Office heating and cooling This IS Green economy Schaffhausen, 28 June 2013 Page 22

23 Questions Thank you for your attention! Questions? Schaffhausen, 28 June 2013 Page 23

Use of transcritical CO 2 in industrial applications

Use of transcritical CO 2 in industrial applications Why CO 2 in industrial? Commercial needs customer needs it Customers want natural solutions (NH3 not always wanted) Customers want non-toxic solutions