CN103660861A - LNG bus cold energy recovering system - Google Patents

Abstract

An LNG bus cold energy recovering system comprises a single chip microcomputer, a temperature sensor, a mode selection circuit, a heat exchanger, an air inlet valve, a tail gas valve, an outlet valve, a high-temperature pipeline, a lower-temperature pipeline and a fan. According to the LNG bus cold energy recovering system, cold energy is converted into cold air to be transmitted into a bus to cool the interior of the bus and also transmitted to an engine to cool the engine, and meanwhile high-temperature tail gas can be led to the engine to preheat the engine.

Description

A kind of LNG bus cold recovery system

Technical field

The present invention relates to a kind of cold recovery system, LNG bus cold recovery system particularly, the energy-conserving and environment-protective technical field that affiliated technical field is energy recycling.

Background technology

In prior art, along with the fast development of economic society, China PM2.5 pollutes aggravation.The regions such as Beijing-Tianjin Ji, Yangtze River Delta, the Delta of the Pearl River, occur that the number of days that gray haze is polluted reaches more than 100 days every year, and indivedual cities surpass 200 days, have a strong impact on residents ' health.Study on monitoring shows, the main source of PM2.5 has: motor-vehicle tail-gas dirt, fuel oil dirt, sulfate, kitchen fumes dirt, construction cement dirt, coal smoke dirt, nitrate etc., wherein motor-vehicle tail-gas dirt reaches 38% to the contribution margin of PM2.5, is positioned at first.

In order to alleviate environmental problem, China greatly develops LNG passenger vehicle.End 2011,45.33 ten thousand of the existing LNG buses in the whole nation.Expect the year two thousand twenty, the whole nation 800,000 the LNG buses of having an appointment.In LNG bus fuel, containing cold is 872kJ/kg, and the existing technological means of utilizing only limits to cooling bus engine, and major part is lost in environment, causes huge waste.On the other hand, the a/c system of existing bus is still used compression-type refrigeration technology, and under air conditioning condition, its energy consumption accounts for 15%～18% of driving engine energy consumption.If the cold in LNG is converted into cold wind, be transported in car, both reduced the waste of LNG cold, reduce again driving engine energy consumption, kill two birds with one stone.

Summary of the invention

LNG is extensively used as bus fuel as green clean energy resource, and its cold containing is about 872kJ/kg, and prior art not yet fully reclaims its cold, causes the waste of cold.Meanwhile, the power consumption of the a/c system of bus accounts for the 15%-18% of engine power.

The present invention is directed to the cold energy that LNG bus fuel contains and reclaim, designed the a/c system that a set of LNG of utilization cold is bus compartment cooling in summer.This system plate fin type heat exchanger of connecting in LNG bus system, coordinates temp measuring system, control system etc., reclaims LNG cold for bus air conditioner refrigeration.If the LNG bus in the whole nation 60% is installed native system, (by moving duration every day 8 hours) will save approximately 6.09 * 104t gasoline every year, reduce 1.57 * 105t carbon-dioxide emission, and effects of energy saving and emission reduction is remarkable.

Concrete technical scheme is as follows:

A LNG bus cold recovery system, this recovery system comprises micro controller system, temperature sensor, mode selection circuit, H Exch, air inlet valve, tail gas valve, outlet valve, high-temperature pipe, cryogenic piping and fan;

Wherein, described mode selection circuit is for realizing the selection of mode of operation, and high level is mode of operation in summer, and low level is mode of operation in winter;

Described micro controller system is used for reading described mode selection circuit input end level, if read level for high, and inlet open, tail gas valve and outlet valve are closed, and fan is started working; If read level, be low, air inlet valve is closed, and tail gas valve and outlet valve are opened, and fan quits work;

Temperature sensor is for feedback regulation vehicle interior temperature, and when entering mode of operation in summer, if current vehicle interior temperature, higher than predetermined work temperature, strengthens suction quantity, rotation speed of the fan is accelerated; If current vehicle interior temperature, lower than predetermined work temperature, reduces suction quantity, rotation speed of the fan reduces, and finally makes vehicle interior temperature be stabilized in predetermined work room temperature place;

Described H Exch for summer mode of operation by cryogenic piping, cold is caused in car and to realize cooling and to cause driving engine, be engine cooling; Described H Exch for winter mode of operation by high-temperature pipe, high-temperature tail gas is caused to driving engine, be engine preheating.

Wherein, described air inlet valve, tail gas valve, outlet valve is respectively air inlet two-port valve, tail gas two-port valve, outlet two-port valve.

Accompanying drawing explanation

Fig. 1 is LNG bus cold recovery system fundamental diagram in summer of the present invention;

Fig. 2 is LNG bus cold recovery system fundamental diagram in winter of the present invention;

Fig. 3 is fin surface temperature distributing analog figure;

Fig. 4 is that heat-exchanger pipeline of the present invention is in kind;

Fig. 5 is LNG bus cold recovery working-flow figure of the present invention;

Fig. 6 is LNG bus cold recovery system 3D modelling of the present invention;

Fig. 7 is that H Exch of the present invention is in kind;

Fig. 8 is leaving air temp and cooling water temperature curve.

 

The specific embodiment

Below in conjunction with the drawings and specific embodiments, technical scheme of the present invention is described in detail.

When system works is compartment cooling, as shown in Figure 1, Figure 2, the high pressure LNG of-160 ℃ enters carburetter and expands, cold exports to fin district by the heat pipe as cryogenic piping, outside high temperature air (summer, the temperature of asphalt coating can reach 65～70 ℃) blasts heat-exchanger fin district by fan and absorbs cold, and temperature is reduced to 4～10 ℃, and wherein a part enters compartment along cold air distribution pipeline and realizes cooling, another part enters engine water-cooling system for water, for driving engine carries out cooling.For not affecting bus normal operation, introduce heat-exchanger fin district by part high-temperature tail gas heat passed through to the heat pipe delivery heat exchanger inside as high-temperature pipe winter, and heating low temperature LNG, does preheating for LNG enters engine combustion.

1. design premises: the simulation of LNG parameter quantification and fin surface temperature traverse

For convenience of calculating, suppose that LNG is comprised of pure methane, in fluid reservoir internal state, be-141.8 ℃, pressure is 0.3～0.6MPa.The intake temperature of driving engine is 10-40 ℃.LNG vaporization is 170～200 ℃ with latent heat, the Exchange of apparent heat temperature difference that air carries out.Through consulting reference materials, the vapourizing temperature of R600a is-14 ℃, and temperature of solidification is-160 ℃, in this device operating temperature interval, has suitable character and state, so this device selects R600a as the cycle fluid of heat pipe.

Conditions setting, through fluent software simulation, obtains fin surface temperature profile as shown in Figure 3.

Temperature be the room air of 27 ℃ after over-heat-exchanger, temperature is reduced to 13 ℃ of left and right.By analysis, hot air rate of volume flow is many greatly for LNG rate of volume flow, so fin frosting concentrates on top, fin district and Cryogenic air exit, therefore adjusting heat-exchanger fin distributes, increase fin district upper fins spacing, increase the length of heat pipe, can effectively reduce frosting.

2. design difficulty: heat converter structure design

Calculating is with reference to Wu Yezheng chief editor < < Small Refrigerating Equipment > > mono-book.The long LNG bus of the 12m of take is example, and its air consumption is 17kg/h.Press LNG vaporization to-10 ℃ of calculating, the latent heat of vaporization of LNG is 525.4kJ, and specific heat capacity is 2.14kJ/ (m2 K), and its vaporization is to the cold of 10 ℃ of releases at 889.2kJ/kg, and refrigerating capacity is 4.2kW.

As calculated, the required heating area of air side is 2.7 ㎡, and heat pipe requirement is 36, and diameter is 10mm, and length 250mm can meet the heat transfer requirement of this device.

Due to market, this device heat pipe of buying in kind is that diameter is 10mm, long 30mm.Internal working medium is water, and operating temperature interval is 0-250 ℃, and power is 60W, thermal resistance coefficient≤0.08(℃/w).Selected heat pipe material object as shown in Figure 4.

3. design focal point: electrical equipment conceptual design

Reduced instruction set computer 8-bit High-Speed Microcontroller--the ATmega16 that control program is developed by atmel corp, temperature sensor, mode selection circuit, air inlet two-port valve, tail gas two-port valve, outlet two-port valve and fan form.

(1) Rule of judgment is definite:

A mode of operation is selected: user selects switch on circuit to realize the selection of mode of operation by master mode.Regulation: high level is mode of operation in summer, and low level is mode of operation in winter.

B refrigerating fan service condition is judged: by AVR micro controller system read mode, select circuit input end level.If read level for high, inlet open, tail gas valve and outlet valve are closed, and fan is started working; If read level, be low, air inlet valve is closed, and tail gas valve and outlet valve are opened, and fan quits work.

C temperature feedback regulates: if enter mode of operation in summer, temperature sensor is for feedback " compartment " room temperature, if current room temperature, higher than predetermined work room temperature, strengthens suction quantity, rotation speed of the fan is accelerated; If lower than predetermined work room temperature, reduce suction quantity, rotation speed of the fan reduces, and finally makes ambient-temp-stable at predetermined work room temperature place.

(2) concrete control program

After powering on, the native system process of automatically starting working is as follows: detecting pattern is selected circuit input end level, if high level enters mode of operation in summer, if low level enters mode of operation in winter.If user selects mode of operation in summer, inlet open, tail gas valve and outlet valve are closed, and fan is started working, and according to temperature feedback amount adjusting air inflow quantity.Main control process flow figure as shown in Figure 5.

(3) advantage or good effect:

The present invention, by the cold recovery utilization of LNG, for compartment carries out cold air distribution cooling, can reduce engine load, and the effects of energy saving and emission reduction of killing two birds with one stone is remarkable, has larger social benefit.Except LNG bus being reclaimed to cold, also can by change some Fabrication parameter by this application of installation in the recovery of other blue gas colds, as autogas, ethene etc.Its field of application is more extensive.

1. cost estimation

A Master Cost (batch manufacturing)

Material	Stainless steel materials	Heat pipe	Electromagnetic valve	Controller	Amount to
						Quantity	-	36	3	1	-
Price/unit	200	180	36	30	446

；

B over-the-road expense

Initial stage treating cost	100 yuan
		Year maintenance cost	100 yuan

2. economic benefit

This apparatus structure is simple, it is simple and easy to produce, power savings advantages is obvious, and the LNG bus that is applicable to various models is installed and used, and drops into batch manufacturing and applies on LNG bus and can reduce engine load 1.23kW to 1.5kW.Press gasoline meter No. 92, the gasoline 0.1～0.12Kg that saves per hour, by 8.5 yuan/kg of No. 92 gasoline, this car air-conditioning is used 8 hours every day, 3 months just can cost recovery.

3. social benefit

End 2011, approximately there are 45.33 ten thousand of LNG buses in China.If this device is installed on 60% vehicle on existing market, will, for country saves approximately 6.09 * 104t gasoline, reduce 1.57 * 105t carbon-dioxide emission every year.After transformation, will effectively save the energy, and greatly reduce the discharge of urban waste gas.

4. expand and promote

The present invention, as the dedicated heat exchanger of LNG released cold quantity, can be general on a lot of equipment, such as transporting fresh van cooler, take LNG as fuel, in ice chest body, lay this H Exch, need not extraneously supply with cold energy and just can keep low temperature in case (annual available).Except giving LNG released cold quantity, also can to other blue gas, carry out cold release by changing some Fabrication parameter, as autogas, ethene etc.It has wide range of applications, and has larger effects of energy saving and emission reduction and social benefit.

Claims (2)

1. a LNG bus cold recovery system, is characterized in that, this recovery system comprises micro controller system, temperature sensor, mode selection circuit, H Exch, air inlet valve, tail gas valve, outlet valve, high-temperature pipe, cryogenic piping and fan;

Wherein, described mode selection circuit is for realizing the selection of mode of operation, and high level is mode of operation in summer, and low level is mode of operation in winter;

Described micro controller system is used for reading described mode selection circuit input end level, if read level for high, and inlet open, tail gas valve and outlet valve are closed, and fan is started working; If read level, be low, air inlet valve is closed, and tail gas valve and outlet valve are opened, and fan quits work;

Temperature sensor is for feedback regulation vehicle interior temperature, and when entering mode of operation in summer, if current vehicle interior temperature, higher than predetermined work temperature, strengthens suction quantity, rotation speed of the fan is accelerated; If current vehicle interior temperature, lower than predetermined work temperature, reduces suction quantity, rotation speed of the fan reduces, and finally makes vehicle interior temperature be stabilized in predetermined work room temperature place;

Described H Exch for summer mode of operation by cryogenic piping, cold is caused in car and to realize cooling and to cause driving engine, be engine cooling; Described H Exch for winter mode of operation by high-temperature pipe, high-temperature tail gas is caused to driving engine, be engine preheating.

2. LNG bus cold recovery system as claimed in claim 1, is characterized in that, described air inlet valve, and tail gas valve, outlet valve is respectively air inlet two-port valve, tail gas two-port valve, outlet two-port valve.

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