Nano-fluid heat absorbing type photovoltaic-solar energy heat pump system
Technical field
The invention belongs to application of solar energy field, more particularly, to a kind of nano-fluid heat absorbing type photovoltaic-solar heat pump
System.
Background technology
Energy problem is the matter of utmost importance of socio-economic development.In recent years, along with the fast development of economy, China is to energy
The trend of rapid growth is presented in the demand in source.At present, because the fossil energies such as the low and coal of China's efficiency of energy utilization make
It result in that energy problem of China is more acute and environmental disruption is on the rise with proportion is excessive, greatly constrain China's economy
Development.Solar energy is important traditional energy substitute because the advantages of its is renewable and environmentally friendly.Solar energy at present
Application mode be mainly photothermal deformation and opto-electronic conversion.
How to be all efficiently the emphasis of research all the time using solar energy, solar photoelectric/photothermal comprehensively utilizes
(PV/T, Photovoltaic/Thermal) is all significantly improved than single optical-electronic system or optical and thermal system, typically
Solar energy PV/T heat collectors are topmost one layer of glass cover-plates, and centre is air layer, and beneath is photovoltaic cell and its substrate layer;
Copper pipe is welded with behind photovoltaic cell substrate, is heat-exchange working medium, generally water in copper pipe.
The transfer process of solar energy is:Solar radiation arrives first at glass cover plate surfaces, most solar radiation meetings
Through glass cover-plate, there is sub-fraction to be reflected and absorbed by cover plate and dissipate;Through among the solar radiation arrival of glass cover-plate
Air layer, centre air layer in, be still the overwhelming majority solar radiations can through centre air layer reach photovoltaic
Battery surface, but equally also have sub-fraction due to multiple reflections between scattering, photovoltaic cell and glass cover-plate, air layer
The reasons such as absorption dissipate;The solar radiation on photovoltaic cell surface is reached, a part is that electric energy is (main by photovoltaic cell sorption enhanced
If visible light part), remaining is then completely converted into heat energy (mainly infrared part);The electric energy changed into can be direct
Utilize, and the heat energy converted is dissipated to environment China and foreign countries except small part, others can be absorbed by photovoltaic cell and its substrate so that light
The temperature rise of battery and substrate is lied prostrate, copper pipe is then passed in the form of heat transfer the temperature of copper pipe is raised;Copper afterwards
Working medium in Guan Yuguan transfers thermal energy to working medium, the temperature rise of working medium under the comprehensive function of heat transfer and convection current.By with
The transmittance process of upper solar energy can be seen that the solar energy part being efficiently absorbed and change into electric energy, and a part, which has changed into, to be followed
The heat energy of ring working medium, remaining is then dissipated due to thermal resistance.
The mode that common PV/T heat collectors absorb using the back side, can from solar energy transmittance process above
Go out, the shortcomings that PV/T heat collectors have its own:1) raising of the photo-thermal efficiency of system to be to sacrifice photoelectric efficiency to realize, in
Between the presence of air layer reduce system heat waste, but also reduce the solar radiation quantity for reaching photovoltaic cell surface simultaneously;2) light
The laminar structure of volt battery and substrate is more complicated, and middle TPT and EVA thermal resistance are larger, and solar energy heat absorption is mainly logical
The TPT of black is crossed to complete and (also there are some to reduce the TPT number of plies by the way of the japanning of surface in studying), and black
TPT, pitch-dark absorptivity are limited;3) thermal capacitance of photovoltaic cell and its substrate is smaller, and temperature rise is larger after heat absorption, causes the heat of system
Damage larger.
Nano-fluid is that the particle of nanoscale is distributed in base fluid, forms suspension uniformly, stable, nano-fluid
Possess more special thermal radiation property and augmentation of heat transfer property so that nano-fluid has preferably application in field of solar energy
Prospect.Research finds, the nano-fluid such as zinc oxide, silica, alundum (Al2O3) has higher saturating for visible light wave range
Rate is penetrated, there is very high absorptivity in its all band, particularly infrared part, this characteristic of nano-fluid causes positive heat absorption
The PV/T of type is possibly realized.Nano-fluid has high transmissivity (up to 95% or so, more than intermediate air in visible light part
Transmitance), can improve the photoelectric efficiency of system, at the same its all band high-absorbility (infrared part more than 95%, far
Higher than black TPT and pitch-dark absorptivity) the photo-thermal efficiency of system can be improved.The front heat absorption of nano-fluid can simplify PV
The structure of plate, reduce system thermal resistance;And the presence of nano particle increases the thermal conductivity of base fluid, nano-fluid and PV plates are enhanced
Between the coefficient of heat transfer;The thermal capacitance of nano-fluid can greatly reduce system much larger than the thermal capacitance of photovoltaic cell and its substrate
Heat waste.Research has shown that the overall efficiency of the PV/T systems of nano-fluid front heat absorbing type is higher than common PV/T systems.
But the shortcomings that nano-fluid heat absorbing type PV/T systems also have its own in actual applications because nano-fluid with
Photovoltaic cell layer is direct contact (TPT of outer layer can be with waterproof and electric insulation), therefore the temperature of nano-fluid directly affects
The temperature of photovoltaic cell, the problem of same with common PV/T is there is, i.e., as the continuation of circulation, nano-fluid temperature are gradual
Rise, photoelectric efficiency will be affected.Additionally due to nano-fluid is largely made cumbersome, therefore many scholars are studying
Cool down the temperature of nano-fluid when nano-fluid application characteristic by the way of heat exchange, but cold is generally required
The more energy of extra consumption, loses more than gain, and reduce front heat absorbing type nano-fluid PV/T applies possibility, and this is also into existing
In one of urgent problem to be solved.
The content of the invention
It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and provide one kind is ensureing system light
Nano-fluid heat absorbing type photovoltaic-solar energy heat pump system of the coefficient of performance of heat pump is improved while electrical efficiency.
The purpose of the present invention can be achieved through the following technical solutions:
Nano-fluid heat absorbing type photovoltaic-solar energy heat pump system (NE-PV-SAHP, Nanofluids Endothermic-
Photovoltaic Solar Assisted Heat Pump), combine photovoltaic-solar heat pump group part and front heat absorbing type
Nano-fluid component,
Described photovoltaic-solar heat pump group part include direct current compressor, water-cooled condenser, air-cooled condenser, choke valve,
Wind-cooled evaporator, PV evaporators,
Described front heat absorbing type nano-fluid component follows including PV evaporators, nano-fluid storage tank and nano-fluid
Ring pump,
Described water-cooled condenser is in parallel with air-cooled condenser, and described wind-cooled evaporator is in parallel with PV evaporators;
Described nano-fluid storage tank is connected by nano-fluid circulating pump with PV evaporators,
Described photovoltaic-solar heat pump group part and front heat absorbing type nano-fluid component share a PV evaporators, and PV steams
The electric energy output end of hair device connects direct current compressor and nano-fluid circulating pump by power switch respectively, so that PV evaporators
Electric energy output be divided into two parts, electric energy power output should match with direct current compressor, nano-fluid circulating pump respectively.
Preferably, the entrance end of water-cooled condenser, air-cooled condenser, wind-cooled evaporator and PV evaporators is equipped with control
Make the magnetic valve opened and closed.
More preferred, PV evaporators are by the glass cover-plate set gradually from top to bottom, nanometer fluid passage, photovoltaic cell
And substrate, heat-insulation layer composition, described nanometer fluid passage is interior to fill flowable nano-fluid, is provided with described heat-insulation layer
Freon pipeline.
More preferred, the flow direction of nano-fluid is opposite with the flow direction of the freon in freon pipeline.Receive
Meter Liu Ti is zinc oxide, silica or alundum (Al2O3) nano-fluid.
Preferably, wind-cooled evaporator and PV evaporators switch according to different weather conditions uses, described air-cooled condensation
Device and water-cooled condenser switch according to the different demands of user to be used.
By photovoltaic-solar energy heat pump system (PV-SAHP, photovoltaic solar-assisted heat pump)
It is effectively combined with front heat absorbing type nano-fluid PV/T systems.Nano-fluid absorbs to the front of solar radiation can letter
Change the structure of PV/T heat collectors;Simultaneously nano-fluid the grading absorption of solar radiation can be improved heat pump solar energy it is comprehensive
Close utilization ratio;The evaporation ends of heat pump can provide nano-fluid cooling needed for cold, ensure nano-fluid all the time with
PV batteries are flowed through in relatively low temperature front, are advantageous to the photoelectric conversion of photovoltaic cell.In addition, driven with the generating of photovoltaic cell straight
Stream compressor and nano-fluid circulating pump can realize system output and solar radiation input between good adaptivity;
Solar irradiation is stronger, and PV cell outputs are bigger, and the rotating speed of direct current compressor and nanometer circulating pump is faster, and the heat exchange of system is got over
By force, the absorption to solar radiation is more, and vice versa, and the two complements each other, it is only necessary to which Proper Match can be completely achieved certainly
Control, without extra increase control system.Wind-cooled evaporator makes as supplement when solar irradiation is not strong or rainy days
With system can realize round-the-clock running substantially;Water-cooled condenser can meet the needs of user is different with air-cooled condenser, have
It is multi-functional.
Nano-fluid heat absorbing type photovoltaic-solar energy heat pump system (NE-PV-SAHP) and common photovoltaic-solar heat pump system
The absorbing medium that the difference of system (PV-SAHP) is converted into heat energy part in the two to solar radiation is different.Solar radiation turns
The heat energy turned to is made up of two parts, and a part comes from shortwave part, and shortwave part is largely absorbed by photovoltaic cell, but still
There is the heat energy that sub-fraction has changed into photovoltaic cell due to that can not inspire electronics;Another part is long wavelength part, this part
Substantially the heat energy of photovoltaic cell has all been changed into.Common photovoltaic-solar energy heat pump system, the absorption to shortwave part are photovoltaic electrics
Pond, the absorption to long wavelength part are black TPT (or pitch-dark other media of grade), and the direct embodiment of the heat energy of absorption is exactly photovoltaic
The rise of battery and its substrate temperature, then this partial heat energy by heat transfer by thermo-compression evaporation end cryogenic fluid absorb;It is and right
In nano-fluid heat absorbing type photovoltaic-solar energy heat pump system, the absorption to shortwave is also photovoltaic cell, and for long wavelength part
Absorption is nano-fluid, and therefore, the embodiment of the heat energy now absorbed is also made up of two parts:When photovoltaic cell and its substrate
Temperature raises, second, the rise of nano-fluid temperature, is absorbed again by heat transfer by thermo-compression evaporation end cryogenic fluid afterwards
(first heat convection is also wanted between nano-fluid and photovoltaic battery panel here, even but due to the heat exchange of forced circulation light water
Coefficient an order of magnitude all at least higher than the pyroconductivity of common metal, therefore can be neglected here).In nano-fluid heat absorbing type light
Volt-solar energy heat pump system, because shortwave is partially converted into the seldom of heat energy part, therefore the temperature rise of photovoltaic cell is smaller, has
Beneficial to photoelectric conversion;For long wavelength part, because the thermal capacitance of nano-fluid is much larger than the photovoltaic battery panel of common PV/T heat collectors,
Therefore the temperature rise of nano-fluid is also smaller.In the case where the evaporation ends working medium coefficient of heat transfer is certain, the low temperature difference means more preferably
Heat energy transmission, i.e., higher solar thermal utilization rate.
Compared with prior art, it is of the invention by photovoltaic-solar energy heat pump system (PV-SAHP) and front heat absorbing type nanometer stream
Body PV/T systems are effectively combined, and solve that front heat absorbing type nano-fluid PV/T system nano-fluids are hydronic to ask
Topic, while improve the solar energy composite utilization rate and the coefficient of performance of heat pump.With front cooling type nanometer common at present
Fluid PV/T systems are compared, and system solves the problem the cooling problem of nano-fluid, improve the photoelectric efficiency of PV batteries;Heat pump
The multifunctionality for the system that adds is introduced, compared with common photovoltaic-solar energy heat pump system, the system can simplify PV/T collection
The structure of hot device, and without additionally increasing control section;The unique optical properties of nano-fluid can be by solar energy spoke simultaneously
The shortwave hit is from long wave respectively with different Absorption of Medium, there is provided the solar thermal utilization rate of heat pump, is ensureing system
The coefficient of performance of heat pump is improved while photoelectric efficiency of uniting.
Brief description of the drawings
Fig. 1 is the structural representation of the present invention;
Fig. 2 is the structural representation of PV evaporators.
In figure, 1 is direct current compressor, and 2 be air-cooled condenser, and 3 be water-cooled condenser, and 4 be choke valve, and 5 be air-cooled evaporation
Device, 6 be PV evaporators, and 7 be nano-fluid storage tank, and 8 be nano-fluid circulating pump, and 9 be glass cover-plate, and 10 be nano-fluid
Passage, 11 be photovoltaic cell and substrate, and 12 be heat-insulation layer, and 13 be freon pipeline, and V1~V8 is magnetic valve, and S1 opens for power supply
Close.
Embodiment
The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.
Embodiment
Nano-fluid photovoltaic-solar energy heat pump system (NE-PV-SAHP), its structure is as shown in figure 1, mainly include direct current
Compressor 1, air-cooled condenser 2, water-cooled condenser 3, choke valve 4, wind-cooled evaporator 5, PV evaporators 6, nano-fluid storage water
Case 7, the grade of nano-fluid circulating pump 8 component, control valve, power switch S1, also corresponding connection member.
Wherein, direct current compressor 1, air-cooled condenser 2, water-cooled condenser 3, choke valve 4, wind-cooled evaporator 5PV evaporators 6
Etc. constituting photovoltaic-solar heat pump group part, PV evaporators 6, nano-fluid storage tank 7, nano-fluid circulating pump 8 and power supply
Switch S1 etc. constitutes front heat absorbing type nano-fluid component.Photovoltaic-solar heat pump group part and front heat absorbing type nano-fluid
Component shares PV evaporators 6.Water-cooled condenser 3 is in parallel with air-cooled condenser 2, and wind-cooled evaporator 5 is in parallel with PV evaporators 6.Receive
Meter Liu Ti storage tanks 7 are connected by nano-fluid circulating pump 8 with PV evaporators 6, and the electric energy output end of PV evaporators 6 passes through confession
Electric switch S1 connects direct current compressor and nano-fluid circulating pump respectively, so that the electric energy output of PV evaporators 6 is divided into two
Part, electric energy power output should match with direct current compressor 1, nano-fluid circulating pump 8 respectively.
Magnetic valve V2, magnetic valve V4 are respectively provided with the entrance and exit of air-cooled condenser 2;The entrance of water-cooled condenser 3
Magnetic valve V1, magnetic valve V3 are respectively provided with outlet.Magnetic valve V5 is respectively provided with the entrance and exit of wind-cooled evaporator 5, electricity
Magnet valve V7;The entrance and exit of PV evaporators is respectively provided with magnetic valve V6, magnetic valve V8, and said modules are realized in fact so as to convenient
When control.
The structures of PV evaporators is as shown in Fig. 2 glass cover-plate 9 by setting gradually from top to bottom, nanometer fluid passage 10,
Photovoltaic cell and substrate 11, heat-insulation layer 12 form, the flowable nano-fluid of filling in nanometer fluid passage, such as can use
Zinc oxide, silica or alundum (Al2O3) nano-fluid, heat-insulation layer 12 is interior to be provided with freon pipeline 13.The flowing of nano-fluid
Direction is opposite with the flow direction of the freon in freon pipeline.
It is the work introduction of the present invention below:
(1) heating
Now condensation end is opened using air-cooled condenser 2, i.e. magnetic valve V2, magnetic valve V4, magnetic valve V1, magnetic valve
V3 is closed;
When solar irradiation is good, evaporation ends use PV evaporators 6, i.e. magnetic valve V6, and magnetic valve V8 is opened, magnetic valve
V5, magnetic valve V7 are closed, and power switch S1 is on-state;Circulation loop is 1 → air-cooled condenser of direct current compressor 2 → throttling
6 → direct current compressor of valve 4 → PV evaporators 1;
When solar irradiation is bad, evaporation ends use wind-cooled evaporator 5, i.e. magnetic valve V5, and magnetic valve V7 is opened, electricity
Magnet valve V6, magnetic valve V8 are closed, and for power switch S1 to disconnect state, circulation loop is 1 → air-cooled condenser of direct current compressor 2
4 → wind-cooled evaporator of → choke valve, 5 → direct current compressor 1;
(2) domestic hot-water is produced
Now condensation end is opened using water-cooled condenser 3, i.e. magnetic valve V1, magnetic valve V3, magnetic valve V2, magnetic valve
V4 is closed;
When solar irradiation is good, evaporation ends use PV evaporators 6, i.e. magnetic valve V6, and magnetic valve V8 is opened, magnetic valve
V5, magnetic valve V7 are closed, and power switch S1 is on-state;Circulation loop is 1 → water-cooled condenser of direct current compressor 3 → throttling
6 → direct current compressor of valve 4 → PV evaporators 1;
When solar irradiation is bad, evaporation ends use wind-cooled evaporator 5, i.e. magnetic valve V5, and magnetic valve V7 is opened, electricity
Magnet valve V6, magnetic valve V8 are closed, and power switch S1 disconnects state, circulation loop be 1 → water-cooled condenser of direct current compressor 3 →
4 → wind-cooled evaporator of choke valve, 5 → direct current compressor 1;
The absorbed process of solar radiation is as follows in PV evaporators 6:Solar radiation is irradiated on glass cover-plate 9 first,
Solar radiation through glass cover-plate 9 produces refraction in nano-fluid, and shortwave part is radiated at photovoltaic electric through nano-fluid
Pool surface produces substantial amounts of electric energy and a small amount of heat energy, long wavelength part are absorbed into the heat energy of nano-fluid by nano-fluid;
The heat energy that the heat energy and nano-fluid that photovoltaic cell absorbs absorb passes to freon pipeline 13, freon pipeline by heat transfer
13 transfer heat to liquid freon with the freon working medium heat convection in pipe, and phase occurs after the heat absorption of freon liquid working substance
Become Freon gas after change.So far, the solar energy part being efficiently absorbed changes into electric energy, and a part changes into working medium
Latent heat of phase change.
In addition, the present invention is mainly the front heat absorption of embodiment nano-fluid and the combination of photovoltaic-solar heat pump, with reference to rear
The two can be mutually beneficial complementary, the performance realized jointly improves, and the present invention mainly embodies the two theory combined.Air-cooled condensation
The multifunctionality for being added to extension system of device and wind-cooled evaporator.Therefore it is all in nano-fluid front heat absorbing type PV/T
System and photovoltaic-solar energy heat pump system be combined into core small change (such as change evaporator, the heat exchange mode of condenser,
Bypass is added between evaporator or condenser at two, changes the type of compressor or miscellaneous part, changes the kind of nano-fluid
Class etc.) in scope of patent protection of the present invention.