Heating and ventilation system

Abstract

The utility model provides a heating and ventilation system, which is characterized by comprising an air compressor, a cooling fan and an exhaust pipe, the fresh air conditioning system comprises a fresh air pipe of the fresh air conditioning system; the connecting air pipe is used for connecting an air compressor cooling fan exhaust pipe and a fresh air pipe of a fresh air conditioning system; the first proportional electric air valve (1) is mounted on the connecting air pipe; the first proportional electric air valve (1) is installed on an air outlet of an air outlet pipe of a cooling fan of the air compressor, the second proportional electric air valve (2) is installed on an air outlet of an air outlet pipe of a cooling fan of the air compressor, and the PLC control system is used for controlling the opening degree proportion of the first proportional electric air valve (1) and the second proportional electric air valve (2).

Description

Technical Field

[0001] The utility model relates to a heating and ventilation system, in particular to a factory power heating and ventilation system. Background Art

[0002] At present, the HVAC systems of factories in the semiconductor, biopharmaceutical, and photovoltaic industries basically use chillers / hot water boilers + air conditioning cabinets for basic temperature and humidity control. The main form of air conditioning cabinets is fresh air conditioning systems, which are the key equipment for temperature and humidity control in the target area, especially in seasons with large differences in temperature and humidity between indoors and outdoors.

[0003] In the autumn and winter seasons when the outside temperature is low, the fresh air conditioning system of the HVAC system inhales low-temperature air from the outside, heats it in the "preheating plate" for initial adjustment, goes through the humidity adjustment section, and then adjusts the temperature in the "reheating plate" to finally reach the required operating temperature (without considering clean filtration). During this period, "preheating" and "reheating" will consume a lot of heat to heat the cold air coming in from the outside, which is ultimately consumed in the form of gas or electricity.

[0004] The compressed air system (also known as the air compressor) releases a large amount of heat during the air compression process, which needs to be cooled by a cooling fan or a water cooling system. The large amount of waste heat of the air-cooled air compressor is sent to the outside through the cooling fan and discharged as hot exhaust air; the waste heat of the water-cooled air compressor is consumed in the form of electrical energy through cooling water heat exchange.

[0005] The annual average energy consumption of the entire HVAC system accounts for 25-35% of the total energy consumption of the factory. In seasons with large differences in indoor and outdoor temperature and humidity, the energy consumption of the HVAC system's fresh air conditioning system can reach about 40% of the HVAC system's energy consumption. The annual average energy consumption of the HVAC system's air compressor accounts for about 10% of the total energy consumption of the factory.

[0006] Therefore, reducing the energy consumption of heat source equipment in the HVAC system is an urgent problem to be solved. Utility Model Content

[0007] One aspect of the utility model provides a heating and ventilation system, characterized in that it comprises: an air compressor, including an exhaust duct of an air compressor cooling fan; a fresh air air conditioning system, including a fresh air duct of the fresh air air conditioning system; a connecting duct, used to connect the exhaust duct of the air compressor cooling fan and the fresh air duct of the fresh air air conditioning system; a first proportional electric air valve (1), installed on the connecting duct; a second proportional electric air valve (2), installed on the exhaust port of the exhaust duct of the air compressor cooling fan, and a programmable logic controller (PLC) control system, used to control the opening ratio of the first proportional electric air valve (1) and the second proportional electric air valve (2).

[0008] One aspect of the utility model provides a HVAC system, characterized in that a new three-way opening is opened in the exhaust duct of the cooling fan of the air compressor, and a new three-way opening is opened in the fresh air duct of the fresh air air-conditioning system, wherein the newly opened three-way opening of the fresh air air-conditioning system has the same specifications as the newly opened three-way opening of the cooling fan, and the two newly opened three-way openings are connected by a connecting air duct.

[0009] One aspect of the utility model provides a HVAC system, characterized in that the aperture of the newly opened three-way opening of the air compressor cooling fan exhaust duct is greater than or equal to the original aperture of the air compressor cooling fan exhaust duct.

[0010] One aspect of the utility model provides a heating and ventilation system, characterized in that the control logic of the PLC control system is set so that the opening ratio of the first proportional electric air valve (1) increases while the opening ratio of the second proportional electric air valve (2) decreases synchronously, or the opening ratio of the first proportional electric air valve (1) decreases while the opening ratio of the second proportional electric air valve (2) increases synchronously.

[0011] One aspect of the utility model provides a HVAC system, characterized in that the total opening ratio of the first proportional electric air valve (1) and the second proportional electric air valve (2) is equal to 1.

[0012] One aspect of the utility model provides a HVAC system, characterized in that it also includes: a fresh air duct temperature and humidity sensor of the fresh air air conditioning system, which is used to detect the fresh air value of the fresh air duct, and the detected fresh air value includes the preheating enthalpy value, preheating temperature, and humidity of the fresh air.

[0013] One aspect of the utility model provides a HVAC system, characterized in that, when the detected fresh air value is higher than the preset fresh air target value, the PLC control system controls so that the first proportional electric air valve (1) is closed and the second proportional electric air valve (2) is fully opened.

[0014] One aspect of the utility model provides a HVAC system, characterized in that, when the detected fresh air value is lower than the preset fresh air target value, the PLC control system controls so that the first proportional electric air valve (1) is opened according to the proportion of the PLC instruction and the second proportional electric air valve (2) is closed according to the proportion of the PLC instruction until the detected fresh air value reaches the preset fresh air target value.

[0015] One aspect of the utility model provides a HVAC system, characterized in that, among the preset target values ​​of fresh air, the preset target value of preheating enthalpy is 41 kj / kg, the preset target value of preheating temperature is 22°C, and the preset target value of humidity is 45%.

[0016] One aspect of the utility model provides a HVAC system, characterized in that the exhaust duct of the air compressor cooling fan is a positive pressure exhaust duct with a duct pressure of about 50 Pa; the fresh air duct of the fresh air air conditioner is a negative pressure suction duct with a duct pressure of about -25 Pa. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a HVAC system according to an embodiment of the utility model. DETAILED DESCRIPTION

[0018] Before proceeding to the following detailed description, it may be advantageous to set forth the definitions of certain words and phrases used throughout this patent document. The terms "coupling", "connection" and their derivatives refer to any direct or indirect communication or connection between two or more elements, regardless of whether those elements are in physical contact with each other. The terms "transmission", "reception" and "communication" and their derivatives cover direct and indirect communication. The terms "include" and "comprising" and their derivatives refer to including but not limited to. The term "or" is inclusive, meaning and / or. The phrase "associated with..." and its derivatives refer to including, including within, interconnecting, containing, contained within, connecting or connecting with, coupling or coupling with, communicating with, cooperating, interweaving, parallel, close to, binding or binding with, having, having attributes, having a relationship or having a relationship with, etc. The term "controller" refers to any device, system or part thereof that controls at least one operation. Such a controller can be implemented with hardware, or a combination of hardware and software and / or firmware. The functions associated with any particular controller can be centralized or distributed, whether local or remote. The phrase "at least one of", when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one of the items in the list may be required. For example, "at least one of A, B, C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, A and B and C.

[0019] Definitions for other specific words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior and future uses of such defined words and phrases.

[0020] In this patent document, the application combination of modules and the division level of sub-modules are only used for illustration, and the application combination of modules and the division level of sub-modules may have different forms without departing from the scope of the present disclosure.

[0021] This article focuses on the fresh air air conditioning heating conditions in the autumn and winter heating season. In autumn and winter, the fresh air air conditioning system of the HVAC system consumes a lot of heat to heat the cold air coming in from the outside. In contrast, the air compressor of the HVAC system releases a lot of waste heat during the air compression process. A lot of waste heat is discharged as hot exhaust or through cooling water heat exchange, resulting in a huge waste of energy.

[0022] In order to solve the above problems, the present invention uses a large amount of waste heat released by the air compressor of the HVAC system for the fresh air system of the HVAC system to reduce the energy consumption of the heat source equipment.

[0023] The invention concept of the utility model is as follows: the exhaust duct of the air compressor cooling fan is connected to the fresh air duct of the fresh air air conditioner, and an electric proportional air valve is installed on the connecting pipe, and the opening ratio of the electric air valve is controlled according to the feedback of the temperature sensor behind the fresh air duct. Specifically, when the detection value of the temperature and humidity sensor of the fresh air duct is higher than the calculated temperature of the temperature control zone, the connecting pipe air valve is closed; when it is lower than the calculated temperature of the temperature control zone, the opening ratio of the connecting pipe air valve is adjusted, and the execution logic is controlled by the HVAC system PLC control system. The air compressor cooling fan is a positive pressure exhaust, and the air duct pressure is about 50pa. The fresh air duct of the fresh air air conditioner is a negative pressure of -25pa. The air flow efficiency is higher from the hot air discharged by the air compressor cooling fan to the fresh air intake of the fresh air air conditioner, and the load of the air compressor cooling fan and the fresh air air conditioner fan is significantly reduced.

[0024] The purpose of the utility model is to utilize the waste heat of the air compressor cooling exhaust air to mix and heat the fresh air before it enters the fresh air air-conditioning system when the outdoor temperature is lower than the calculated temperature of the temperature control zone, which can greatly reduce the energy consumption of the "preheating section" and "reheating section" of the fresh air air-conditioning and achieve the purpose of energy saving.

[0025] Figure 1 It is a schematic diagram of a HVAC system according to an embodiment of the utility model.

[0026] refer to Figure 1 The HVAC system of the embodiment of the utility model comprises: an air compressor, a fresh air conditioning system, a connecting air duct connecting the air compressor and the fresh air conditioning system, a first proportional electric air valve (1) installed on the exhaust port of the exhaust duct of the air compressor cooling fan, a second proportional electric air valve (2) installed on the connecting air duct, and a programmable logic controller (PLC) control system for controlling the opening ratio of the first proportional electric air valve (1) and the second proportional electric air valve (2).

[0027] A tee is opened on the exhaust duct of the air compressor cooling fan (of equal diameter or larger), and a tee is opened on the fresh air duct of the fresh air air conditioning system. The specifications are the same as those of the tee opened on the cooling fan, and then the two newly opened tee openings are used as connecting air ducts.

[0028] A first proportional electric air valve (1) is installed on the connecting air duct, and a second proportional electric air valve (2) is installed at the exhaust port of the original air compressor cooling fan. The control signals of the first proportional electric air valves (1) and 2 are connected to the fresh air air conditioning PLC control system.

[0029] Set the PLC control logic: the first proportional electric air valve (1) and 2 are interlocked, one opens and the other closes, and the total opening ratio of the two valves is equal to 1. "The sum of the total opening ratios of the first proportional electric air valve (1) and the second proportional electric air valve (2) is equal to 1" means that the sum of the total opening ratios of the two proportional electric air valves is equal to 100%. "1" is 100%, which means fully open. For example, if the opening ratio of the first proportional electric air valve (1) is 40%, the opening ratio of the second proportional electric air valve (2) should be 60%, in order to prevent back pressure from being generated in the exhaust duct of the air compressor cooling fan, and to prevent high temperature caused by poor exhaust of the air compressor. For another example, when the outdoor temperature is 15°C and the target temperature of the temperature control area is 22°C, in this case, if all the hot air discharged by the air compressor enters the fresh air duct, it will cause excess heat; then this embodiment only needs the first proportional electric air valve (1) to open 30%, so that a small amount of hot air mixed with the outdoor temperature 15°C fresh air can reach the target temperature of 22 degrees; at this time, the opening ratio of the second proportional electric air valve (2) should be 70%. In the process of the outdoor temperature gradually dropping to 10°C, the opening ratio of the first proportional electric air valve (1) of this embodiment increases with the heat demand, and gradually increases the opening ratio to 80%. A large amount of hot air mixed with the outdoor temperature 8°C fresh air can maintain the target temperature of 22 degrees. At this time, the opening ratio of the second proportional electric air valve (2) is also synchronously reduced to 20%.

[0030] According to the feedback of the original fresh air duct temperature sensor (i.e., the detected fresh air value), the opening ratio of the first proportional electric air valve (1) and the second proportional electric air valve (2) is controlled according to the set target (the preheating enthalpy value target is 41 kj / kg, the preheating temperature target is 22°C, and the humidity target is 45%). The sum of the opening ratios of the first proportional electric air valve (1) and the second proportional electric air valve (2) is equal to 1, wherein the opening ratio change of the first proportional electric air valve (1) and the second proportional electric air valve (2) is controlled by the control logic of the PLC control system. Specifically, when the fresh air value detected by the original fresh air duct temperature and humidity sensor is higher than the fresh air target value, the first proportional electric air valve (1) is closed, and the second proportional electric air valve (2) is fully opened (the opening ratio is 100%), that is, when the fresh air value detected by the original fresh air duct temperature and humidity sensor is higher than the fresh air target value, the first proportional electric air valve (1) is fully closed, that is, the opening ratio is 0 (because there is no heat demand for the fresh air); at this time, the second proportional electric air valve (2) is fully opened (the opening ratio is 100%), and the heat is discharged to the outside. When the fresh air value detected by the original fresh air duct temperature and humidity sensor is lower than the fresh air target value, the first proportional electric air valve (1) is opened according to the proportion of the PLC instruction, and the second proportional electric air valve (2) is closed according to the proportion of the PLC instruction until the feedback of the original fresh air duct temperature sensor reaches the preset target.

[0031] According to the experimental conditions of this embodiment in Shanghai area, the following are: a class 1000 clean room with constant temperature and humidity, a controlled temperature of 22±2°C, a relative humidity of 45±5%, an area of ​​1500 square meters, a height of 6.5 meters, a ventilation frequency of 25 times, and a room pressure of 20pa. The fresh air air conditioning system is designed to have a fresh air volume of 28000m3 / h according to the cleanliness level, process exhaust volume, and personnel density, and the actual detected air volume is 25000m3 / h. The air compressor generates a lot of heat when compressing air, and needs to be cooled by air cooling or water cooling. Take an air-cooled air compressor with a rated exhaust volume of 20m3 / min as an example: the cooling air volume is 28800m3 / h, and the measured exhaust air temperature is 13°C higher than the inlet air temperature.

[0032] The experimental data of this embodiment are as follows: when the outside temperature is lower than 8°C, the first proportional electric air valve (1) of the connecting pipe is fully opened, the opening ratio of the second proportional electric air valve (2) is 0, and the waste heat utilization rate of the air compressor is 90%; according to the air volume of 25000m3 / h, the temperature rise of 12°C, the air density of 1.29kg / m3, the specific heat capacity of normal pressure air is 1006,

[0033] Simple estimate of heat = mass (volume × density) × specific heat × temperature rise:

[0034] 25000×1.29×1006×12=389322000 joules=93009.0258 kcal

[0035] The conversion success rate unit is 108.145kw*h.

[0036] The following takes Shanghai as an example to estimate the annual energy required when using air compressor waste heat:

[0037] 1. In the three months of winter, the average daily temperature is below 8°C for 15 hours (heat efficiency

[0038] 1), then 108kwh*15h*90d*1=145800kwh; above 8℃ for 9 hours, the average temperature is calculated as 12℃ (heat efficiency 0.7), then 108kwh

[0039] *9h*90d*0.7=61236kwh; total winter energy is 145800+61236=207036kwh.

[0040] 2. In the six months of autumn and winter, the average daily temperature is below 22°C for 12 hours, and the average temperature is calculated as 15°C (heat efficiency 0.5), then 108kwh

[0041] *10h*180d*0.5=97200kwh

[0042] 3.0 in summer.

[0043] In summary, the annual energy required in Shanghai when using air compressor waste heat is 207036kwh+97200kwh=304236kw*h.

[0044] The following is an example of Shanghai where the annual energy required without using the waste heat of the air compressor is measured:

[0045] According to actual measurements, under the conditions of an outside fresh air temperature of 8°C and a relative humidity RH of less than 75%, this embodiment can increase the fresh air temperature by 12°C; when the target temperature of the temperature control zone is 22±2°C and the outside temperature is 8°C or above, this embodiment does not require other auxiliary heat sources; that is, auxiliary heat sources are only required when the outside temperature is below 8°C.

[0046] Therefore, the difference in heat energy between using and not using air compressor waste heat is the time period below 8°C. This example uses Shanghai to estimate the annual energy required without using air compressor waste heat. In Shanghai, the outside temperature is below 8°C for only 3 months in winter, which lasts for 15 hours a day, and the average temperature in these 15 hours is 5°C, so at least a temperature rise of 15°C is required. According to the above method, the estimated heat per hour = mass (volume × density) × specific heat capacity × temperature rise:

[0047] 25000×1.29×1006×15=486652500 joules=116261.28 kcal, converted into a power unit of 135.18 kw*h. Total energy required for three months in winter:

[0048] 135.18kwh*15h*90d*1=182493kwh. Considering the constant heat energy in other time periods, the annual energy required without using the waste heat of the air compressor is 340929kw*h.

[0049] ·Ratio of energy saving using and not using waste heat from air compressor (heat energy)

[0050] 304236 / 340929*100%=89.237%

[0051] According to the embodiments of the utility model, when the outdoor temperature is lower than the calculated temperature of the temperature control zone, the waste heat of the air compressor cooling exhaust air is used to mix and heat the fresh air before entering the fresh air air-conditioning system, which can greatly reduce the energy consumption of the "preheating section" and "reheating section" of the fresh air air-conditioning and achieve the purpose of energy saving.

[0052] Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

[0053] Any description in this utility model should not be construed as implying that any particular element, step or function is an essential element that must be included in the scope of the claims. The scope of the patent subject matter is limited only by the claims.

Claims

1. A HVAC system, characterized in that: include: Air compressor, including air compressor cooling fan exhaust duct; Fresh air air conditioning system, including fresh air duct of fresh air air conditioning system; Connecting air duct, used to connect the exhaust duct of the air compressor cooling fan and the fresh air duct of the fresh air conditioning system; A first proportional electric air valve (1) is installed on the connecting air duct; The second proportional electric air valve (2) is installed at the exhaust port of the air compressor cooling fan exhaust duct. A programmable logic controller (PLC) control system is used to control the opening ratio of a first proportional electric air valve (1) and a second proportional electric air valve (2).

2. The HVAC system according to claim 1, characterized in that: Open a new three-way port on the exhaust duct of the air compressor cooling fan, and open a new three-way port on the fresh air duct of the fresh air conditioning system. The specifications of the new three-way port of the fresh air conditioning system and the new three-way port of the cooling fan are the same, and Connect the two newly opened three-way ports through the connecting air duct.

3. The HVAC system according to claim 2, characterized in that: The aperture of the newly opened three-way opening of the air compressor cooling fan exhaust duct is greater than or equal to the original aperture of the air compressor cooling fan exhaust duct.

4. The HVAC system according to claim 1, characterized in that: The control logic of the PLC control system is set so that the opening ratio of the first proportional electric air valve (1) increases while the opening ratio of the second proportional electric air valve (2) decreases synchronously, or the opening ratio of the first proportional electric air valve (1) decreases while the opening ratio of the second proportional electric air valve (2) increases synchronously.

5. The HVAC system according to claim 1, characterized in that: The total opening ratio of the first proportional electric air valve (1) and the second proportional electric air valve (2) is equal to 1.

6. The HVAC system according to claim 1, characterized in that: Also includes: The fresh air duct temperature and humidity sensor of the fresh air air conditioning system is used to detect the fresh air value of the fresh air duct. The detected fresh air value includes the preheating enthalpy value, preheating temperature and humidity of the fresh air.

7. The HVAC system according to claim 6, characterized in that: When the detected fresh air value is higher than the preset fresh air target value, the PLC control system controls so that the first proportional electric air valve (1) is closed and the second proportional electric air valve (2) is fully opened.

8. The HVAC system according to claim 6, characterized in that: When the detected fresh air value is lower than the preset fresh air target value, the PLC control system controls so that the first proportional electric air valve (1) is opened according to the proportion of the PLC instruction and the second proportional electric air valve (2) is closed according to the proportion of the PLC instruction until the detected fresh air value reaches the preset fresh air target value.

9. The HVAC system according to claim 7 or 8, characterized in that: Among the preset target values ​​for fresh air, the preset target value for preheating enthalpy is 41 kj / kg, the preset target value for preheating temperature is 22°C, and the preset target value for humidity is 45%.

10. The HVAC system according to claim 1, characterized in that: The exhaust duct of the air compressor cooling fan is positive pressure exhaust, and the duct pressure is about 50Pa; the fresh air duct of the fresh air air conditioner is negative pressure suction, and the duct pressure is about -25Pa.

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