SORPTION HEAT PUMPS AND REFRIGERATORS L.L. Vasiliev Belarus – Indian Workshop “Advances in sorption based thermal devices, 2 – 3 November 2004 Luikov Heat & Mass Transfer Institute, Minsk, Belarus

INTRODUCTION and air-conditioning in regions free of grid electricity Developing countries extremely need for heat pumping, refrigeration, and air-conditioning in regions free of grid electricity Concept of ammonia, CO2, water and hydrogen as a nature friendly working fluids for sorption technologies Short Time Cycles sorption machines with dual sources of energy (solar/gas, solar/electricity) Concept of combined action of Physical Adsorption and Chemical Reactions Heat Pipes for sorption heat pumping, solar cooking and refrigerators Sorption technologies for natural gas and hydrogen storage and transportation

The goal is: TO DESIGN A REFRIGERATOR, which: would operate without grid electricity; consuming a cheap energy (solar energy concentrator and autonomous, low pressure adsorbed natural gas storage system); can be built and maintained in the country of use; would operate with ammonia, or water as refrigerant; be light and portable; be low enough in cost.

Sorption heat pump, refrigerator and transformer Working fluids: ammonia, water, methanol, CO2 , hydrogen, hydrocarbons Sorbent materials: silica-gel, zeolite, active carbon, metal chlorides, metal nitrates, metal hydrates, metal carbonates, metal hydrides, ets. Cycles: heat production, cold production, heat and cold production, heat transformation, heat and cold storage, gas storage and transportation, gas compression Cascades: one, two, three ,ets.

Specific surface for different active carbons (BET)

Sorption capacity and specific density of methan adsorption on different active carbons

Activated carbon materials as sorbents Activated carbon fiber “BUSOFIT” Multiplied by 50000 times Multiplied by 10000 times Multiplied by 50 times Activated carbon (timber product) Activated carbon material (timber product) Specific pore surface 1200 m2 /g Low cost Multiplied by 30 times Multiplied by 1000 times

SORBENT BED – COMPLEX COMPAUND “Busofit” “Busofit” + CaCl2

NEW SORBENT COMPLEX COMPOUND ACTIVATED CARBON FIBER “BUSIFIT”- METAL CHLORIDE The most favourable situation for the RESORPTION HEAT PUMPS is the case, when the presence of a liquid phase is impossible + SALTS : BaCl2 , NiCl2 , MnCl2 ACF “BUSOFIT” (multiplied in 10000 times) ADVANTAGES OF BUSOFIT AS A SALT HOST MATERIAL high rate of adsorption and desorption; uniform surface pore distribution (0.6-1.6 nm); few macropores (0.1-0.2 mm), 0.5-2 m2/g; few mesopores with 50 m2/g; relatively high thermal conductivity SALT = “Busofit” actions as a fast reacting material COMPLEX COMPOUND (multiplied in 10000 times)

Sorption heat machine condenser desorber evaporator adsorber

Three different modification of sorption machine

SORPTION-GAS REFRIGERATOR MAIN DESIGN HIGH TEMPERATURE PART LOW TEMPERATURE PART WATER LOOP THERMAL CONTROL SYSTEM AMMONIA REFRIGERATOR

SOLAR-ELECTRIC REFRIGERATOR HIGH TEMPERATURE PART

Solar/gas sorption refrigerator

SOLID SORPTION REFRIGERATOR VIEW and CHRACTERISTICS 1 – Evaporator 2 – Adsorber No.1 3 – Adsorber No.2 General view

ISOTHERMAL PANEL-HEAT PIPES Schematic of the “spaghetti” heat pipe panel Photo of "Spaghetti" heat pipe panels inside the testing chamber 1 – condenser of the heat pipe, 2 – evaporator of the adsorption refrigerator, 3 – porous structure, 4 – heat pipe evaporator

Sorption refrigerator for cold generation and drying 1 – sorption heat pipe (SHP), 2 – heat pipe for sorbent bed cooling, 3 – condenser for SHP, 4 – evaporator for SHP , 6 – sorbent material, 7 – cooling chamber, 8 – heat pipe panel “Spaghetti”, 9 –drying chamber, 10 – perforated panel.

SOLAR-GAS REFRIGERATOR MAIN PARAMETERS Solar-gas reactor L = 1.2; D = 0.05 m “Busofit” mass in the reactor 0.75 kg CaCl2 in one reactor 0.32 kg Ammonia mass in one reactor 0.92 kg Water mass in one reactor 1 kg Ammonia mass in the pulsating HP 0.05 kg Total mass of the refrigerator 22 kg Temperature of the hot reactor surface 120 0C Condenser temperature 50 0C Cabinet evaporator temperature (without heat pipes) -18 0C Heating capacity (W/kg sorbent) 850

TWO REACTORS RESORPTION HEAT PUMP Envelope Fin Sorbent Vapor volume Water heat exchanger Vapour entrance channel Liquid Resorption two reactors heat pump with heat pipe thermal control Reactor with sorbent bed Temperature and Pressure Evolutuin During RHP Reactors heating/cooling

Three sorbers sorption machine VAPOUR DYNAMIC THERMOSYPHONS THE CAPILLARY PUMPED EVAPORATOR “SPAGHETTI” НЕАТ PIPE High temperature NiCl2 + “Busofit”, mean temperature MnCl2 + “Busofit”, and low temperature BaCl2 + “Busofit”

SIX REACTORS RESORPTION HEAT PUMP steam Clapeyron diagram of three- effect resorption system with a temperature lift near 100 0C. Six reactors Resorption Heat Pump

SIX REACTORS RESORPTION HEAT PUMP Three-effect resorption system (BaCl2 , MnCl2, NiCl2). 1 – cold generation in A3 BaCl2 reactor, 2 – heat generation in B3 BaCl2 reactor, 3 – heat flow in the two-phase water system inside of heat exchangers of MnCl2 and NiCl2 reactors, 4 – energy supply by heat pipe HP1 and HP2 electric heating elements Temperature field in: 1 – water entrance. 2 – water in A3 BaCl2 reactor, 3 –water in B3 BaCl2 reactor, 4 – water two-phase flows in MnCl2 and NiCl2 reactors

Six adsorbers sorption heat pump for heat production and cold generation

The ANG vessel 7 cylinders, total volume of 43 dm3 The gas storage capacity of the ANGS (170 - 180 m3/m3) is nearly twice higher as compared to a traditional compressed NG storage 1 – valve for gas charge; 2 – pressure gauge ; 3 – valve; 4 – joint valve for the car engine gas supply ; 5 – perforated tube for radial gas distribution; 6 –sorbent bed; 7,8 – ANG vessel

An advanced 14 cylinder ANG vessel with a heat pipe thermal control inside for methane storage and transportation 1 – vessel envelope; 2 – heating elements (heat pipes); 3 – sorbent bed; 4 – gas channels; 5 – metal fins to heat/cool a sorbent bed

ANG systems potential applications Vessels for vehicles (CNG tanks alternative) Gas fired solid sorption heat pumps and refrigerators, air-conditioning devices ANG storage systems - gas holders for peak shaving operations Gas fired drying chambers ANG big tanks transportation LPG (propane) replace systems Emergency fuel, etc.

CONCLUSIONS 1 A solar - gas/electrical solid sorption refrigerator with 1.8 m2 collection surfaces is an efficient nature friendly sorption machine. The ratio between solar energy and gas, or electrical energy supply is automatically maintained on the level of 1 kW. The COPR of the refrigerator is near 0.44. The combination - an active carbon fiber “Busofit” + CaCl2 in one reactor with the porous evaporator (sublimator) is very promising for the designing of the portable and light autonomous cooler for ground, space and hazardous applications.

CONCLUSIONS 2 An experimental set-up based on the COMLEX COMPOUNDS NiCl2, MnCl2, BaCl2 – ACTIVE CARBON FIBER „Busofit“ demonstrated a possibility to have a RESORPTION HEAT PUMP with simultaneous heat (superheated water vapor T = 120 0C – 130 0C) and chilled water production (T = 3 0C – 50C) with COP (without internal and external heat recovery) ~1.2. Heat recovery by the heat pipe thermal regulation and internal mass regeneration between the reactors out of phase could increase this COP up to 1.4-1.5. The RESORPTION HEAT PUMP with a heat output 1400-1500 W is an autonomous, portable device, allowing the user to apply this system in space, or on the ground (underwater, underground) and to supply, or postpone the heating and cooling capacity and to control the heat and cold output. The device has no moving parts, is noiseless and light. The pressure control regulation of the heat pump action is the most reliable and simple.