JPH0264255A - Cogeneration system by internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain a great economic effect by using an external energy source of only an internal combustion engine so that roughly 100% waste heat energy is furnished so as to be utilized when a thermo-electric ratio for demand is greater than a thermo-electric ratio for generation. CONSTITUTION:The thermal load 40 of the cooling/heating and hot water supply ing equipment is furnished with the waste heat energy Q1 of an internal combus tion engine 1 as input thermal energy wherein the equipment is provided with an electro-thermal energy conversion system such as an electrically driven heat pump and the like. And when these are not sufficient enough in capacity (Q3/WL1>Q1/WL), a part WL2 of the output power WL of a generator 2 is input ted through a switch S2 so as to be converted into thermal energy QL2 thereafter by the electro-thermal energy conversion system. Then, the energy is added to waste heat energy Q1 so that the load can also be furnished with total ther mal energy Q2(=Q1+QL2) while being controlled in such a way that the total thermal energy Q2 will come close to the thermal demand Q3 of the thermal load 40 through the opening/closing actuation of the switch S2.

Description

[Detailed Description of the Invention] "Industrial Application Field" Demands for both electric loads and heat loads such as air conditioning equipment can be met by both the electric power source obtained by driving a generator with an internal combustion engine and the waste heat energy source. Regarding the system that makes it possible to pay for it.

2. Prior Art -a Hotels, hospitals, buildings, factories, etc. are equipped with air-conditioning and hot water supply equipment, which is a heat load, and require a heat source for this purpose. The power for this heat source and electric load is usually obtained from a commercial power source, but in recent years, for the purpose of energy saving, it has increasingly been obtained from a cogeneration internal combustion power generation device installed on the consumer side. This cogeneration internal combustion power generation device is configured to supply electric power obtained by driving a generator using an internal combustion engine to an electrical load, and also to supply exhaust heat energy discharged from the internal combustion engine to heating, cooling, and oil supply equipment, which are heat loads. Conventionally, a system configuration as shown in FIG. 2 is generally known.

This will be explained below. In this system, the internal combustion engine 1 drives the generator 2 to generate the required electric power WL (
=WL1), and is supplied to the electric load 3 with the demand power amount WL1, and is also discharged from the internal combustion engine 1 and can be used effectively.

The system is configured to supply heat according to the demand Q, to a heat load 4 such as air conditioning/heating/hot water equipment, etc., for effective use.

By the way, in this system, the so-called generated thermoelectric ratio Q*/WL, which is the ratio of the electric power WL obtained by driving the power generation R2 with the internal combustion engine 1 and the effectively usable waste heat energy ffi Qs emitted from the internal combustion engine 1, is determined by its use. However, the so-called demand heat-to-power ratio Q 3 / W L 1 is the ratio of the electrical load WL, i on the demand side and the heat load Q of the air conditioning/hot water supply equipment. Q x /
It is extremely rare for W L t and Q t / W t to match, and it is far more likely that they differ considerably.

Therefore, in the conventional example shown in FIG.
/WLI>Ql /wt, ), the shortage is supplemented using an external energy source (not shown) such as a commercial power source (and a new heat load that uses this as a dedicated energy source), and vice versa. If it becomes excessive (Q i /
W L 1 < Q t / W L ) is configured to radiate the excess heat using a radiator (not shown) or the like. Therefore, there is a problem in that extra equipment such as commercial power supply equipment and a radiator is required, which increases equipment costs and operating costs accordingly, impairing economic effects.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve the problems of the conventional system described above, when the demand thermoelectric ratio Q i / W L 1 is larger than the generated thermoelectric ratio Q s / '#V L In,
By using an external energy source that saves only the internal combustion engine 1, and without replenishing using an external energy source such as a commercial power source (and a new heat load that uses this as a dedicated energy source), It is an object of the present invention to provide a highly economically effective system configuration that always utilizes nearly 100% of effectively usable waste heat energy Q1 even when L t fluctuates to cover both WLI and Q.

"Means and actions for solving the problem" In order to achieve this object, the following means were adopted in this invention.

The heat load (40) such as air conditioning and hot water supply equipment includes an electric/thermal conversion device such as an electric heat pump type, and the effectively usable exhaust heat energy (Q1) of the internal combustion engine (1) is used as the input thermal energy source. It can also be covered by only Qi
/ Wt, t> Q t /WL> is the generator (2)
The − part (w L 2 ) of the output power (WL) of is inputted through the switch (S2) and converted into thermal energy <QL1) by the electricity/thermal conversion device, and then added to the waste heat energy (Q1). Total thermal energy <Q2
) (Qt +QL1), and is controlled so that this total thermal energy (Q2) always approaches the demand heat Q1) of the heat load (40) by opening the switch (S2).

That is, the generated thermoelectric ratio Q t / W L (= w t, t ) when the switch (S2) is opened is smaller than the demand thermoelectric ratio Q i / W L s on the load side, and Q
When Ql is insufficient for 3, close the switch (S2) and increase WL by WL2, WL=WLl+WL2
Therefore, Q is also increased by a commensurate amount (ΔQ), and the total thermal energy Q2 is obtained by adding the thermal energy Q L 2 minutes obtained from the ~N'L2 minutes above to Q after this increase. By using it as the heat source of the heat load (20), the so-called supply thermoelectric ratio Q 2 / W L 1, which is the ratio of each substantial supply energy to the demand side of both the heat load (20) and the electric load (3), is obtained. Generated thermoelectric ratio Q
1/W L t, and convert this to the demand thermoelectric ratio Q
3/W t, The supply heat and power ratio is controlled so as to approach t.

"Embodiment" Hereinafter, the present invention will be described with reference to an embodiment shown in FIG. In FIG. 1, reference numeral 1 denotes an internal combustion engine that drives a generator 2 that outputs electric power WL, and discharges effectively usable waste heat energy Q1. 3 is an electric load, and all of its power demand ff1WL1 is provided from the output WL of the generator 2. 40 has a heat demand of Q].Although not shown in the figure, it is an air-conditioning/heating system including a suitable heat exchanger such as a waste heat boiler and an electric/thermal conversion device such as an electric heat pump type.
This is the heat load of the hot water supply equipment, and its input energy source can be covered only by the Ql discharged by the internal combustion engine 1. However, in this case, Ql is in Ql, and switch S2 is open), and which Ql If it is insufficient (Q
i / Wt, t > Q t / Wt, ), the switch S2 is closed and the remaining power WL2 (= WL WLI ) minutes, convert it into thermal energy QL2 minutes by an electric heat pump type electricity/thermal conversion device (not shown), etc., and then add the total thermal energy Q2 (=Qt +QL) to Q.
2), and set Q2 to Q,
(in other words, the above-mentioned supply heat and power ratio Qz/
The switch S2 is closed by 1 m so that the demand heat/electric ratio Q,/WLs becomes WLl''y.

Next, in the system shown in FIG.
The generated thermoelectric ratio Q t / W L is 2.0 (the power generation efficiency with respect to the input primary energy of the internal combustion engine 1 is 0.2
Taking as an example the case where the effectively usable waste heat recovery rate is 0.533 and the combined heat efficiency is 0.8), the relationship between the energy amounts of each part will be explained with reference to FIG. (However, the power demand W1 of electric load 3 is taken as 100% standard. Also, losses in each part are ignored.) In Fig. 3, the horizontal axis is the input primary energy amount P of the internal combustion engine rJA1, and the vertical axis is the input primary energy amount P of the internal combustion engine rJA1. The energy amount of each part corresponding to it, that is, the a-line is WL
, the a-line indicates WLI (always constant at 100% standard),
The b line shows the a line (WL) plus 08 minutes (that is, the part sandwiched between the b line and the a line is Qs), 3
One point is the intersection of the a line and the a line, the di line is a line parallel to the vertical axis passing through these 88 points, and this d! The intersections of the line, b line, and horizontal axis are points S and Pm. Then, the energy amount of each part when WL2=○ is WL, =WL1= a t
P t (= 100%), Ql = Q Is
= b + a t (= 200%), p = p, =
(wL+Qt)10.8=375%. Therefore, Q is 200% of WLl (demand thermoelectric ratio Q).

/WL1=2), if switch S2 is opened,
The relationship between the amount of energy in each part is determined as described above, so
Effectively usable exhaust heat energy Q of internal combustion engine 1, (=2
00%) is the demand heat uQx (-200
%) and is fully available.

By the way, Q3 is 300% of WLl (Qi/WLI=3
), the supply of energy to the heat load 40 is performed by closing switch S2 in addition to Q, WL2 (QL2).
Total amount of heat energy for both sides Q2
(=Q1 +QL2) is set to 300%, and if the relationship between the energy amounts of each part in this case is shown in Fig. 3, the e-line is drawn by adding 300% of Q to the above-mentioned a-line,
Find the intersection point b2 of this line e and the above-mentioned line b, draw a line d parallel to the vertical axis passing through this point b2, and find the intersection a2 of this line d2 and the above-mentioned line a, a line and the horizontal axis, If at and P2 are found, the relationship between the energy amounts of each part is WL, = a'.

P2 (=100%), WL2 (QL2) = a
2 a t(=33.3%>,Q,=Q,,+ΔQ=b
2a2 (=226.7%), Q2 =Qt +Qt
, 2=Qi (=300%), PmP2 (=50
0%), that is, if P is 500% of WLl, 300% of Q can be supplied in exactly 92 minutes, so Ql is completely utilized.

In addition, △Q = 66.7%, Q L2 = 33.3%
It is.

In addition, although there is one switch S2 in FIG. 1, it is possible to use a plurality of switches if necessary to make the switching width narrower, and also, by using a control device (not shown), Q2 is always adjusted to the maximum possible level. Repeatedly open and close multiple switches S2 to approach .

You can also make it happen.

"Effects of the Invention" In the conventional system shown in FIG. 2, for example, if the generated thermoelectric ratio in the above example is 2 but the demand thermoelectric ratio is 3, the shortage of the heat source for the heat load 4 is 100%. (However, the electric load demand power WL 1 minute is based on 1009.) must be supplemented from an external energy source, and therefore, for example, commercial power supply equipment must be installed to cover at least that amount from a commercial power source. Moreover, the power generation efficiency of this commercial power source for the input primary energy is usually not so good (usually less than 40%), but if the system according to the present invention is adopted, the heat load of 40% can be reduced as described above. All of the required heat can be met by operating only the internal combustion engine 1 without using an external energy source such as a commercial power supply, and moreover, the exhaust heat energy Q, which can always be effectively used even if the heat load 40 fluctuates, can be utilized almost completely, and the overall thermal efficiency with respect to the input primary energy can always be maintained at a state close to the maximum jr3 (usually about 80%). Therefore, equipment costs and operating costs are both low, and extremely large economic effects can be obtained.

[Brief explanation of the drawing]

1 and 2 are diagrams of a combined heat and power generation system using an internal combustion engine-driven power generation device showing an embodiment according to the present invention and a conventional example, respectively, and FIG. 3 shows each part of the combined heat and power generation system of FIG. 1. FIG. 2 is a characteristic diagram showing the relationship between energy amounts. l... Internal combustion engine, 2... Generator, 3... Electrical load, 4.40-... Heat load such as air conditioning/hot water supply equipment, WL
...Power generated by the generator (2), WLl...Power demand of the electrical load (3), WL2-...Power input to the heat load (40), Q,...Power of the internal combustion engine (1) Effectively usable exhaust heat energy to be discharged, Q L4... Thermal energy from which WL2 is converted into heat, Q2... Total thermal energy (=Q. +QL2). α2f=C++cL2) Now Q5 1, Koichitsu-cho-2 1-I- No. 10, Figure 21

Claims (1)

[Claims] In addition to supplying electric power obtained by driving a generator with an internal combustion engine to an electrical load, exhaust heat energy discharged from the internal combustion engine is supplied to a heat load such as an air-conditioning/heating/hot-water supply facility for effective use. In a combined heat and power generation system using an internal combustion engine configured as shown in FIG.
The demand heat and power ratio (Q_3/W_L_1), which is the ratio between the electric power generated by the internal combustion engine (1) and the generator (2) set (W_L), and the effectively usable waste heat energy (Q_1)
In the case where the generated thermoelectric ratio (Q_1/W_L) which is the ratio of You can also switch part (W_L_2) of the output power (W_L) of the generator (2) to the switch (
S_2), and the heat energy (Q_L_2) obtained by heat conversion by an electric heat pump or the like can be covered by the total heat energy (Q_2) (=Q_1+Q_L_2) added to the exhaust heat energy (Q_1), and By opening and closing the switch (S_2), this total thermal energy (Q_2) is converted into the demand heat (
Q_3) A combined heat and power generation system using an internal combustion engine characterized by being always close to Q_3).