CN116929036A - Photovoltaic driven solar heat pump dryer - Google Patents

Abstract

The invention provides a photovoltaic-driven solar heat pump dryer which comprises a drying part, a heat pump part and a solar photovoltaic part, wherein direct current generated by solar photovoltaic is utilized to drive a direct current speed-adjustable heat pump to heat air, and then the hot dry air is used for drying fruits, medicinal materials and other articles. The invention adopts a drying mode with closed circulation heating and heating as main and open circulation heating and heating as auxiliary, and a plate-fin type air-conditioner regenerator is arranged at the outlet of the drying chamber, thereby utilizing waste heat of exhaust gas and recycling condensed water in dried articles. The invention can change the heating capacity, evaporation temperature and condensation temperature of the heat pump cycle by adjusting the rotating speed of the direct current speed-regulating compressor and the opening of the electronic expansion valve, thereby controlling the temperature and humidity of the dry air. The photovoltaic direct-driven solar heat pump dryer can be used for obtaining sanitary and high-drying-quality products and liquid water efficiently according to different external environments, different drying temperatures of articles and different final water content requirements.

Description

Photovoltaic driven solar heat pump dryer

Technical field

The invention relates to a photovoltaic-driven solar heat pump dryer, and in particular to a heat pump drying system driven by solar photovoltaic DC power supply with controllable temperature and humidity of dry air.

Background technique

Heat pump drying has significant energy-saving effect and the drying process is gentle. Compared with traditional electric heating drying, since the efficiency of the heat pump is greater than 1, 3-4kW of heat can be obtained for every 1kW of electricity consumed, so its energy-saving effect is obvious. Compared with traditional sun drying, the hot air provided by heat pumps is clean, stable and gentle. Traditional sun drying is mainly affected by the environment, and the drying quality, drying effect, and drying rate cannot be guaranteed. Therefore, heat pump drying technology has great advantages. Compared with traditional fuel-burning drying, the traditional fuel-burning drying method will burn a large amount of fossil energy, which will not only cause pollution to the environment, but even cause certain pollution to dry items. Heat pumps only consume electricity to heat the air, so their drying The process is very environmentally friendly, and the drying quality and drying effect can be guaranteed.

Contents of the invention

The photovoltaic driven solar heat pump dryer of the present invention can also condense the water evaporated from the items at the evaporator while drying the items. It produces a large amount of water that can be used as domestic water and even drinking water, which is beneficial to drought. Areas are very valuable. In summary, the heat pump drying system is an inevitable trend in the future development of the drying field in the direction of energy conservation and environmental protection.

Existing solar photovoltaic heat pump systems all use inverter devices, which boost and invert the DC power output from solar photovoltaic cells into AC power, and then use the AC power to drive the AC compressor. This process not only increases construction and maintenance costs, but also It will also reduce the utilization efficiency of photovoltaic power generation. The invention introduces a plate-fin air-to-air regenerator, which can recycle and utilize sensible heat in exhaust gas, thereby increasing the drying capacity of the photovoltaic-driven solar heat pump dryer under the same compressor power consumption. At the same time, the invention also introduces a plate-fin air-to-air heat exchanger to dissipate the excess heat of the air in the closed cycle to the environment to maintain the overall energy balance and enable the photovoltaic-driven solar heat pump dryer to operate stably for a long time.

The object of the present invention is to provide a photovoltaic-driven solar heat pump dryer, which uses a solar photovoltaic DC power source to drive a heat pump compressor to provide hot air for drying items.

The object of the present invention is achieved through the following technical solutions. The photovoltaic-driven solar heat pump dryer of the present invention includes: a solar photovoltaic part, which includes solar cell components, power and voltage regulators and control modules; a heat pump part, which includes a DC speed-regulating compressor, an evaporator, a condenser, and electronics. Expansion valve and corresponding pipelines; drying part, which includes drying box, plate-fin air-to-air heat exchanger, plate-fin air-to-air regenerator, duct fan, variable air duct valve and detachable air duct.

In one embodiment, sunlight irradiates the solar cell module to generate electricity. The generated electricity is regulated by the power and voltage regulator through the circuit. The voltage-regulated DC electricity enters the control module to drive and control the DC speed-regulating compressor, electronic expansion valve, Variable air duct valves and fans. The air pipeline and drying box are tightly wrapped with insulation materials. The air pipeline in the drying part is detachable for easy maintenance and cleaning. Use an air pipe to connect the drying box outlet and the hot side inlet of the plate-fin air-to-air regenerator. A pipeline fan is arranged in this pipe; use an air pipe to connect the hot-side outlet of the plate-fin air-to-air regenerator and the hot-side outlet of the plate-fin air-to-air heat exchanger. Side inlet; use an air pipe to connect the hot side outlet of the plate-fin air-to-air heat exchanger and the heat pump evaporator inlet; set a variable air duct valve at the evaporator outlet and the cold-side inlet of the plate-fin air-to-air regenerator; use an air pipe to connect the plate The cold side outlet of the fin-type air-to-air regenerator and the inlet of the heat pump condenser; use an air pipe to connect the condenser outlet and the drying box inlet. A cooling fan is arranged at the cold side inlet of the plate-fin air-to-air heat exchanger. When the variable air duct valve is closed, the cooling fan is turned on. A condensed water outlet is provided at the bottom of the evaporator to facilitate the discharge and collection of condensed water. The hot side of the plate-fin air-to-air heat exchanger flows through the air flowing out of the hot side of the plate-fin air-to-air regenerator. The cold side of the plate-fin air-to-air heat exchanger flows through ambient air. The plate-fin air-to-air heat exchanger circulates part of the air. Heat is dissipated into the ambient air to maintain the energy balance of the closed drying cycle. The hot side of the plate-fin air-to-air regenerator flows through the air flowing out of the drying box, and the cold side of the plate-fin air-to-air regenerator flows through the air flowing out of the evaporator. The plate-fin air-to-air regenerator transfers part of the waste heat of the exhaust gas to the air that is about to enter the condenser, making full use of the waste heat, reducing the sensible heat load of the evaporator, and improving the drying capacity. The variable air duct valve is controlled through the control module. When the variable air duct valve is open, the evaporator outlet and the cold side inlet of the plate-fin air-to-air regenerator are connected to the external environment respectively. At this time, the photovoltaic-driven solar heat pump dryer is in an open cycle; when the variable air duct valve is closed, the evaporator outlet It is connected to the cold side inlet of the plate-fin air-to-air regenerator. At this time, the photovoltaic-driven solar heat pump dryer is in a closed cycle. During the initial operation of the closed drying cycle, the variable air duct valve is opened for a period of time to replenish circulating air, and then closed again. When the ambient temperature is high and the humidity is low, the variable air duct valve is opened so that the photovoltaic-driven solar heat pump dryer operates in an open cycle state. The control module can also adjust the speed of the DC speed-regulating compressor and the opening of the electronic expansion valve according to different external environments and drying requirements, so that the evaporation pressure, condensation pressure, evaporation temperature, condensation temperature, and refrigerant flow rate of the refrigerant cycle are evenly balanced. adjustable. A first temperature and humidity sensor is provided at the inlet of the condenser where the air enters, a second temperature and humidity sensor is provided at the inlet of the drying box, and a third temperature and humidity sensor is provided at the outlet of the drying box. All temperature sensors are connected to the control module. Each temperature and humidity sensor senses the temperature and humidity everywhere and transmits the data to the control module. The control module analyzes the data and completes the control of the heat pump part.

According to one aspect of the present invention, a photovoltaic-driven solar heat pump dryer is provided, which is characterized by comprising:

Solar photovoltaic segment, which includes solar modules, power and voltage regulators and control modules;

Heat pump part, which includes DC speed-regulating compressor, evaporator, electronic expansion valve, and condenser;

The drying part includes a drying box, a pipeline fan, a plate-fin air-to-air heat exchanger, a first temperature and humidity sensor, a second temperature and humidity sensor, a third temperature and humidity sensor, a cooling fan, a plate-fin air-to-air regenerator, and a transformer. Air duct valve.

The beneficial effects of the present invention are mainly reflected in:

The photovoltaic driven solar heat pump dryer of the present invention is a heat pump drying system driven and controlled by solar photovoltaic DC power supply. Using solar photovoltaic DC power drive control technology, the photovoltaic-driven solar heat pump dryer not only increases the heat production per unit power, but also can effectively adjust the working status of the heat pump when driven by solar photovoltaics by controlling the compressor speed and expansion valve opening. Thereby controlling the state of dry air and controlling the entire drying process. This photovoltaic-driven solar heat pump dryer incorporates a plate-fin air-to-air heat exchanger and a plate-fin air-to-air regenerator, which improves waste heat utilization, reduces the energy consumption of the photovoltaic-driven solar heat pump dryer, and improves the energy balance under closed drying. problem, so that the closed mode can run stably for a long time. The invention can also efficiently collect the condensed water of dry matter, which has great practical significance for dry areas. The photovoltaic driven solar heat pump dryer of the present invention saves energy, has high drying efficiency, good drying quality, has little impact on the environment, is convenient to control, is safe and reliable, and is simple to operate.

Description of the drawings

Figure 1 is a schematic diagram of a photovoltaic driven solar heat pump dryer according to one embodiment of the present invention.

Detailed ways

The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, a photovoltaic-driven solar heat pump dryer according to one embodiment of the present invention includes: a solar photovoltaic part, a heat pump part, and a drying part. In the embodiment shown in Figure 1, the solar cell module (1), power and voltage regulator (2), and control module (3) are connected in sequence through insulated wires in the solar photovoltaic part. Use wires to connect the control module (3) to the DC speed-regulating compressor (4) and electronic expansion valve (6) in the heat pump section, as well as the pipeline fan (9), cooling fan (14), and first temperature in the drying section. The humidity sensor (11), the second temperature and humidity sensor (12), the third temperature and humidity sensor (13), and the variable air duct valve (16) are connected. The solar cell module (1) is the power and voltage regulator (2), control module (3) in the solar photovoltaic part, and the DC speed regulating compressor (4), electronic expansion valve (6), DC in the heat pump part B The speed-regulating compressor (4), electronic expansion valve (6), and the pipeline fan (9), cooling fan (14), and variable air duct valve (16) in the drying section C provide electric energy. At the same time, the control module (3) collects temperature and humidity signals from the first temperature and humidity sensor (11), the second temperature and humidity sensor (12), and the third temperature and humidity sensor (13) and converts them into control signals to control the DC speed-regulating compressor ( 4), the opening of the electronic expansion valve (6), the speed of the pipeline fan (9), the speed of the cooling fan (14) and the opening and closing of the variable air duct valve (16). In the heat pump part, the DC speed regulating compressor (4), evaporator (5), expansion valve (6), and condenser (7) are connected with pipelines in sequence to form a heat pump circuit, which is filled with refrigerant. The dry air in the drying part forms a closed or open coupling with the heat pump part through the air pipeline and the variable air duct valve.

As shown in Figure 1, in one embodiment according to the present invention, a drying mode in which closed-type heat recuperation is mainly used and open-type heat recuperation is supplemented is adopted. The heat pump part includes a drying box (8), a pipeline fan (9), a plate-fin air-to-air heat exchanger (10), a first temperature and humidity sensor (11), a second temperature and humidity sensor (12), and a third temperature and humidity sensor. (13), cooling fan (14), plate-fin air-to-air regenerator (15), variable air duct valve (16). Use an air pipe to connect the outlet of the drying box (8) and the hot side inlet of the plate-fin air-to-air regenerator (15). A pipeline fan (9) is arranged in this air pipe; use an air pipe to connect the plate-fin air-to-air regenerator (15). )The hot side outlet and the hot side inlet of the plate fin air-to-air heat exchanger (10); use an air pipe to connect the hot side outlet of the plate fin air to air heat exchanger (10) and the inlet of the heat pump evaporator (5); in the evaporator (5) ) outlet and the cold-side inlet of the plate-fin air-to-air regenerator (15) are provided with a variable air duct valve (16); an air pipe is used to connect the cold-side outlet of the plate-fin air-to-air regenerator (15) and the inlet of the heat pump condenser (7) ; Use an air pipe to connect the outlet of the condenser (7) and the inlet of the drying box (8). A cooling fan (14) is arranged at the cold side inlet of the plate-fin air-to-air heat exchanger (10). The evaporator (5) is provided with a condensed water outlet, and each connection port is sealed and wrapped with insulation material.

When the photovoltaic-driven solar heat pump dryer of the present invention is running, the air in the cycle enters the cold side of the condenser (7) and absorbs the heat of the refrigerant on the hot side of the condenser (7). The temperature increases and the relative humidity decreases. This air with high temperature and low relative humidity enters the drying box (8) to conduct heat and mass transfer with the materials, and takes away the water vapor evaporated from the materials. At this time, the air coming out of the drying box (8) becomes high-temperature and high-humidity air. The air increases its kinetic energy through the pipeline fan (9) and then enters the hot side of the plate-fin air-to-air regenerator (15), transferring the heat to the plate-fin air regenerator (15). The air on the cold side of the fin air-to-air heat exchanger (15) then passes through the hot side of the plate fin air to air heat exchanger (10), transferring heat to the ambient air on the cold side of the plate fin air to air heat exchanger (10). After two sensible heat coolings, it enters the hot side of the evaporator (5) and exchanges heat with the low-temperature refrigerant on the cold side of the evaporator (5). Sensible heat and latent heat exchange occur. At this time, the hot side of the evaporator (5) will Condensed water is generated, and the condensed water is discharged from the water outlet at the bottom of the evaporator (5). During the closed cycle, the variable air duct valve (16) is closed, and the air from the hot side outlet of the evaporator (5) enters the cold side of the plate-fin air-to-air regenerator (15) and the hot side of the plate-fin air-to-air regenerator (15). The air exchanges heat, the temperature rises, and then enters the cold side of the condenser (7) to complete a closed cycle. At this time, all the water vapor evaporated from the material is condensed and discharged by the evaporator (5). A cooling fan (14) is arranged at the cold side inlet of the plate-fin air-to-air heat exchanger (10) to dissipate heat from the hot side circulating air to the environment to maintain energy balance and enable the closed drying cycle to operate normally. When the ambient air temperature is high and the humidity is low or the photovoltaic-driven solar heat pump dryer is in the initial stage of closed drying, the variable air duct valve (16) is opened and the drying cycle becomes an open cycle. There is no energy imbalance problem during the open cycle process, and the cooling fan (14) is turned off at this time. At the same time, fresh outside air enters from the cold side of the plate-fin air-to-air regenerator (15), and exhaust gas is discharged from the hot side outlet of the evaporator (5). The rest of the process is the same as the closed cycle. For open and closed cycles, the introduction of plate-fin air-to-air regenerators can reuse part of the heat in the exhaust gas, condense more liquid water without changing the evaporation load, and improve the entire photovoltaic drive. Drying efficiency of solar heat pump dryers.

The photovoltaic-driven solar heat pump dryer according to the present invention provides electric energy for the entire photovoltaic-driven solar heat pump dryer through photovoltaic components, and at the same time collects signals through sensors and control modules and converts them into control signals, so that the heat pump part and the drying part are energy-saving, efficient and reliable. Dry the dry material in a controlled manner. The closed regenerative drying mode has no direct contact with the external environment and recovers the waste heat of exhaust gas. It is suitable for various situations that require clean and dry conditions, high external environmental humidity and low external environmental temperature; the open regenerative drying mode recycles It eliminates the exhaust heat and is suitable for situations where the external environment is clean, the temperature is high, and the humidity is low.

The above are only specific application examples of the present invention, and do not constitute any limitation on the protection scope of the present invention. Any technical solution formed by adopting equivalent transformation or equivalent substitution shall fall within the scope of protection of the present invention.

Claims (6)

1. A photovoltaic-driven solar heat pump dryer, characterized by comprising:

a solar photovoltaic section comprising a solar module (1), a power and voltage regulator (2) and a control module (3);

the heat pump part comprises a direct-current speed regulation compressor (4), an evaporator (5), an electronic expansion valve (6) and a condenser (7);

the drying part comprises a drying box (8), a pipeline fan (9), a plate-fin type air-air heat exchanger (10), a first temperature and humidity sensor (11), a second temperature and humidity sensor (12), a third temperature and humidity sensor (13), a heat dissipation fan (14), a plate-fin type air-air heat regenerator (15) and a variable air channel valve (16),

a plate-fin type air-air heat exchanger (10) and a plate-fin type air-air heat regenerator (15),

wherein:

a first temperature and humidity sensor (11) is arranged at the inlet of the air inlet condenser,

a second temperature and humidity sensor (12) is arranged at the inlet of the drying box,

a third temperature and humidity sensor (13) is arranged at the outlet of the drying box,

the first temperature and humidity sensor, the second temperature and humidity sensor and the third temperature and humidity sensor are all connected with the control module (3).

The outlet of the drying box (8) is connected with the hot side inlet of the plate-fin type air-air heat regenerator (15) through an air pipeline, a pipeline fan (9) is arranged in the pipeline,

through the hot side outlet of the air pipeline connecting plate fin type air-air heat regenerator (15) and the hot side inlet of the plate fin type air-air heat exchanger (10),

through the hot side outlet of the air pipeline connecting plate fin type air-air heat exchanger (10) and the inlet of the heat pump evaporator (5),

a variable air passage valve (16) is arranged between the outlet of the evaporator (5) and the cold side inlet of the plate-fin type air-space heat regenerator (15),

through the air pipeline connecting plate fin type air-air heat regenerator (15) cold side outlet and the heat pump condenser (7) inlet,

the outlet of the condenser (7) is connected with the inlet of the drying box (8) through an air pipeline,

a heat radiation fan (14) is arranged at the inlet of the cold side of the plate-fin air-air heat exchanger (10),

the hot side of the plate-fin type air-air heat exchanger (10) flows through the air flowing out of the hot side of the plate-fin type air-air heat regenerator (15),

the cold side of the plate-fin air-air heat exchanger (10) flows through ambient air,

the plate-fin type air-air heat exchanger (10) dissipates a part of heat of the circulating air into the ambient air to maintain the energy balance of the closed drying cycle,

the hot side of the plate-fin type air-air regenerator (15) flows through the air flowing out of the drying box (8),

the cold side of the plate-fin type air-air regenerator (15) flows through the air flowing out of the evaporator (5),

the plate-fin type air-conditioning regenerator (15) recovers and utilizes waste heat of exhaust gas,

the solar cell module (1) provides electric energy for a power and voltage regulator (2), a control module (3), a direct current speed regulation compressor (4), an electronic expansion valve (6), a pipeline fan (9), a heat dissipation fan (14) and a variable air passage valve (16).

2. The photovoltaic-driven solar heat pump dryer of claim 1 wherein,

the detachable air pipeline and the drying box (8) are both wrapped by nontoxic heat insulation materials, and a condensed water outlet is arranged at the lower part of the evaporator (5) so that condensed water can be collected.

3. The photovoltaic-driven solar heat pump dryer of claim 1 wherein,

the solar cell module (1) is sequentially connected with the power and voltage regulator (2) and the control module (3) through insulated wires;

the output ends of the control module (3) are respectively connected to the direct-current speed regulation compressor (4), the electronic expansion valve (6), the pipeline fan (9), the heat dissipation fan (14) and the variable air passage valve (16) through insulated wires.

4. The photovoltaic-driven solar heat pump dryer of claim 1, wherein:

the variable air passage valve (16) is controlled by the control module (3), so that:

when the variable air duct valve (16) is opened, the outlet of the evaporator (5) and the cold side inlet of the plate-fin type air-to-air heat regenerator (15) are respectively communicated with the external environment, the heat dissipation fan (14) is closed, the photovoltaic-driven solar heat pump dryer is in open circulation,

when the variable air passage valve (16) is closed, the outlet of the evaporator (5) is communicated with the inlet of the cold side of the plate-fin type air-to-air heat regenerator (15), the heat radiation fan (14) is opened, the photovoltaic driving solar heat pump dryer is in closed circulation,

when the closed drying cycle is operated initially, the variable air passage valve (16) is opened for a period of time to supplement the circulating air, and then closed,

when the ambient temperature is higher and the humidity is lower, the variable air duct valve (16) is opened, so that the photovoltaic-driven solar heat pump dryer operates in an open circulation state.

5. The photovoltaic-driven solar heat pump dryer of claim 1 wherein,

the rotating speed of the direct current speed regulation compressor (4) and the opening degree of the electronic expansion valve (6) can be regulated according to different external environments and the requirements of regulating and drying through the control module, so that the evaporating pressure, the condensing pressure, the evaporating temperature, the condensing temperature and the refrigerant flow of the refrigerant circulation can be regulated.

6. A photovoltaic driven solar heat pump drying method based on a photovoltaic driven solar heat pump dryer according to claim 1, characterized in that:

by controlling the variable airway valve (16) with the control module (3), thereby:

when the variable air duct valve (16) is opened, the outlet of the evaporator (5) and the cold side inlet of the plate-fin type air-to-air heat regenerator (15) are respectively communicated with the external environment, the heat dissipation fan (14) is closed, the photovoltaic-driven solar heat pump dryer is in open circulation,

when the variable air passage valve (16) is closed, the outlet of the evaporator (5) is communicated with the inlet of the cold side of the plate-fin type air-to-air heat regenerator (15), the heat radiation fan (14) is opened, the photovoltaic driving solar heat pump dryer is in closed circulation,

when the closed drying cycle is operated initially, the variable air passage valve (16) is opened for a period of time to supplement the circulating air, and then closed,

when the ambient temperature is higher and the humidity is lower, the variable air duct valve (16) is opened, so that the photovoltaic-driven solar heat pump dryer operates in an open circulation state.