Thermal energy storage facility having functions of heat storage and heat release

Abstract

A thermal energy storage facility for use in heat storage and heat release comprises a heat storage/release mechanism constituted by multiple heat storage/heat exchange units stacked up, each unit at least comprises a heat storage board having parallel grooves for loading phase-change material (PCM) therein and a heat exchange plate having micro-channel groups for heat transfer fluid (HTF) flowed through to exchange heat with the PCM; particularly two or more the thermal energy storage facilities can be worked together by combination in series or/and in parallel to input of thermal energy, absorption of thermal energy and both simultaneously from the PCM, and the thermal energy storage facility capably operating at a heat storage temperature higher than 1200° C. is suited for use in solar thermal power generation system to improve overall efficiency of solar thermal power to reach 35-40%.

What is claimed is: 
     
         1 . A thermal energy storage facility having functions of heat storage, heat release and both, using a phase-change material (PCM) for storing heat and releasing heat, comprising a thermal effect mechanism and at least two convergence-divergence hoods, wherein the improvement comprises:
 the thermal effect mechanism comprises   an external framework functioning as a rigid framework of the thermal effect mechanism; and   a heat storage/release mechanism hermetically sealed by the external framework and comprising multiple heat storage/heat exchange units stacked up, each heat storage/heat exchange unit comprises a heat storage board and a heat exchange plate stacked up, wherein   the heat storage board has a plurality of parallel grooves for loading the PCM therein, and   the heat exchange plate has one or more micro-channel groups functioning as a passage of a heat transfer fluid (HTF), each micro-channel group comprises multiple micro-channel units arranged in parallel to allow the HTF when passed through to exchange heat with the PCM of the heat storage board; and   the convergence-divergence hoods each comprise   a hollow-core cavity disposed outside the heat storage/release mechanism of the thermal effect mechanism and adapted to conceal inlet ends and outlet ends of micro-channel groups of each said heat storage/heat exchange unit of the heat storage/release mechanism; and   a pipe communicating with the hollow-core cavity for feeding or discharging the HTF.   
     
     
         2 . The thermal energy storage facility as described in  claim 1 , wherein the heat storage boards of the heat storage/heat exchange units are of a thickness T 1  of 5-20 mm, and wherein the grooves of the heat storage boards are of a bottom thickness T 2  of 0.3-3 mm, a groove width T 3  of 5-20 mm, and a groove-to-groove spacing T 4  of 0.3-3 mm. 
     
     
         3 . The thermal energy storage facility as described in  claim 1 , wherein the heat exchange plate has two spaced-apart Z-shaped micro-channel groups. 
     
     
         4 . The thermal energy storage facility as described in  claim 2 , wherein the heat exchange plates of the heat storage/heat exchange units are of a thickness of 1-4 mm. 
     
     
         5 . The thermal energy storage facility as described in  claim 2 , wherein the micro-channel units of the micro-channel groups of the heat exchange plates are of a channel depth of 0.5-1.5 mm, a channel width of 1.0-3.0 mm and a wall thickness of 0.3-1.5 mm between every two adjacent micro-channel units. 
     
     
         6 . The thermal energy storage facility as described in  claim 2 , wherein the micro-channel unit of the heat exchange plate is shaped as a semicircular having a diameter of 1.0-3.0 mm. 
     
     
         7 . The thermal energy storage facility as described in  claim 1 , wherein the PCM is one or more molten salts selected from the group consisting of Li 2 CO 3 , LiF, NaF, KF, MgF 2 , CaF 2 , CaO, mixture of 46.5% LiF/11.5% NaF/42% KF, mixture of 80.5% LiF/19.5% CaF 2  and mixture of 66.3% NaNO 3 /33.7% KNO 3 , afore clamed PCMs materials in combination with graphite form, afore clamed PCMs encapsules. 
     
     
         8 . The thermal energy storage facility as described in  claim 6 , wherein the PCM further contains graphite or metal added. 
     
     
         9 . The thermal energy storage facility as described in  claim 6 , wherein the thermal energy storage facility operates at a heat storage temperature equal to or higher than of 1000° C. 
     
     
         10 . The thermal energy storage facility as described in  claim 6 , wherein the thermal energy storage facility operates at a heat storage temperature ranged from 700° C. to 1500° C. 
     
     
         11 . The thermal energy storage facility as described in  claim 6 , wherein the thermal energy storage facility operates at a heat storage temperature higher than 1500° C. 
     
     
         12 . A large-scale thermal energy storage facility for use in a solar power generation system to effectuate thermal energy storage, comprising two or more thermal energy storage facilities of  claim 1  are connected in parallel, connected in series or connected by a combination of both.