WO2017060135A1

WO2017060135A1 - Heater device and method for operating a heater device

Info

Publication number: WO2017060135A1
Application number: PCT/EP2016/073064
Authority: WO
Inventors: Luis Miguel Pacheco Monteiro
Original assignee: Bosch Termotecnologia S.A.
Priority date: 2015-10-07
Filing date: 2016-09-28
Publication date: 2017-04-13
Also published as: EP3359879A1; PT108869A

Abstract

The invention relates to a heater device having at least one open-loop and/or closed-loop control unit (12) for determining an air ratio (λ_c) of a combustion process. According to the invention, the open-loop and/or closed-loop control unit (12) is provided for determining the air ratio (λ_c) on the basis of an input power (P_in) and an ionization current (I) in at least one operating state.

Description

Description Title:

A heater apparatus and method of operating a heater apparatus

State of the art

Gas-powered heaters are known from the prior art, which include a control and / or regulating unit for determining an air ratio. The determination of the air ratio may be effected, for example, based on a temperature of a heating flame, an ionisation signal of the heating flame and / or on the basis of an exhaust gas sensor signal.

Disclosure of the invention

The invention relates to a heater device with at least one computing and / or evaluation unit, which is intended to determine an air ratio of a combustion.

It is proposed that the computing and / or evaluation unit is provided to determine the air ratio based on an input power and an ionization current in at least one operating state.

In this context, a "heater device" should be understood as meaning, in particular, at least one part, in particular a subassembly, a heater and, preferably, a continuous flow heater. at least one modulatable and / or switchable blower for supplying a combustion air and / or at least one modulatable and / or switchable Fuel control valve for supplying a fuel include. In this context, a "heating unit" should be understood to mean, in particular, a unit which is intended to convert energy, in particular bioenergy and / or preferably fossil energy, in particular directly into heat and, in particular, to supply it to a fluid, advantageously water Heating unit at least one heating module, which is intended in particular to burn a mixture, in particular a mixture of a combustion air and a fuel, and advantageously at least one heat exchanger , formed and advantageously has a thermal for heating the fluid

Connection to the heat exchanger. In particular, the term "provided" should be understood to mean specially programmed, designed and / or equipped.Assuming that an object is intended for a specific function should in particular mean that the object fulfills this specific function in at least one application and / or operating state and / or performs.

A "control and / or regulating unit" should also be understood to mean, in particular, an electrical and / or electronic unit having at least one control electronics unit. "Control electronics" is intended in particular to mean a unit having a computing unit and a memory unit as well as a control unit Memory unit stored operating, control and / or control program are understood, which is in particular intended to be executed by the arithmetic unit. In particular, the control and / or regulating unit is provided to provide at least one control signal for setting and / or adjusting a blower, in particular a blower for combustion air and / or the fuel control valve for fuel. Furthermore, the control and / or regulating unit is provided to provide a heating power, in particular a requested heating power and / or a desired heating power, by adjusting and / or adjusting the fan and / or the fuel control valve.

An "air ratio" is to be understood in particular as a factor that depends in particular on the combustion air and / or the fuel, which determines a quality of the combustion and / or on the basis of which a quality of the combustion can be concluded from an amount of combustion air actually contained in the mixture, in particular in the mixture of the combustion air and the fuel, to a stoichiometric amount. iometrically required amount of combustion air, which is particularly needed for complete combustion. An air ratio which has the value 1 corresponds in particular to a stoichiometric combustion air ratio. Advantageously, the air ratio corresponds to a, in particular direct and / or indirect, control and / or controlled variable. To achieve optimized combustion, in particular a stable heating flame, a minimum pollutant emission and / or a maximum efficiency, a desired air ratio is in a slightly lean mixture range, in particular the mixture of the combustion air and the fuel, and in particular between 1, 15 and 1 , 45, preferably between 1, 2 and 1, 4 and more preferably between 1, 25 and 1, 35.

In this context, an "input power" is to be understood in particular as one of the heating unit, in particular the heating module, in particular a momentary and / or currently supplied, in particular maximum achievable, power, in particular thermal, performance, which is especially true for a complete and / or In this case, the input power is correlated in particular with a chemical energy contained and / or stored in the fuel, in particular the fuel supplied to the heating unit, Preferably, the heater device has at least one ionization probe. which is intended to detect an ionization current within a combustion flame, In particular, the ionization current is correlated with the air ratio.

By such a configuration, a generic heater device can be provided with advantageous operating characteristics. In particular, by

Use of the input power and the ionisationsstroms an advantageously reliable and / or exact determination of the air ratio over a whole power range of a heater, in particular a heater with a power modulating, air-number-controlled gas blower, are possible. Furthermore, an optimized combustion with a stable heating flame, a minimal heating effect, can be advantageous

Pollutant emissions and / or maximum efficiency can be ensured, which in particular a reliability can be increased.

If the control and / or regulating unit is provided to determine the input power on the basis of an output power and a thermal efficiency, in particular the combustion and / or the heating unit, in particular of the heating module, in particular special to determine and / or, advantageously analytically, to calculate, an advantageous precise and / or simple determination of the input power, in particular without affecting a heating operation can be achieved. In this context, an "output power" is to be understood as meaning, in particular, instantaneous and / or instantaneous output power. Advantageously, the output power corresponds to a power supplied to the fluid and / or absorbed by the fluid, in particular thermal power, the output power being, in particular, a thermal energy which, in particular during combustion, results from the chemical energy of the fuel. Furthermore, the output power is correlated with the input power, in particular via an enthalpy, in particular combustion enthalpy, The thermal efficiency could, for example, be designed as a reference value and in particular in the memory unit of the control and / or Be deposited control unit. Advantageously, however, the control and / or regulating unit is provided to determine the thermal efficiency at least based on an input temperature of the combustion air, in particular the combustion air flow, and / or the fuel, in particular the fuel flow, and / or an exhaust gas temperature of the combustion. For this purpose, the heater device preferably has at least three sensors, in particular at least one exhaust gas temperature sensor, which is provided for detecting the exhaust gas temperature of the combustion, and at least one temperature sensor for the combustion air and / or the fuel. It is further proposed that the control and / or regulating unit is provided to determine the output power based on a temperature of a fluid, preferably an inlet temperature and / or an outlet temperature, in particular of the heat exchanger, and / or a fluid flow, in particular by the heat exchanger , in particular to determine and / or, advantageously analytically, to calculate. Preferably, the heater device has at least one temperature sensor, which is provided to detect an input temperature and / or an outlet temperature of the fluid. By the use of simply constructed sensors with a high fatigue strength and / or small aging fluctuations, an advantageously precise measurement can be achieved. It is further proposed that the heater device has at least one flow meter, which is intended to detect a particular current and / or current fluid flow. In particular, the flow meter can be designed as an acoustic, a gyroscopic, a magneto-inductive, mechanical volumetric, optical and / or thermal flow meter.

Through the use of conventional flow meters, an advantageously precise measurement can be achieved with advantageously low costs.

In a further embodiment of the invention, it is proposed that the computing and / or evaluation unit is provided to determine a fluid flow on the basis of at least one performance characteristic of a fluid pump. In particular, the heater device comprises at least one sensor, which is provided to detect the at least one performance characteristic, in particular continuously and in particular wirelessly and / or by means of a "performance characteristic value" In particular, the at least one sensor can be integrated into the fluid pump or be arranged as a separate element outside the fluid pump Preferably, the performance characteristic is formed by a pump speed and / or an electrical power consumption of the fluid pump In particular, the heater device can have at least one current sensor which is provided to detect, in particular continuously, a current consumption of the fluid pump Alternatively or additionally, the heater device can comprise at least one rotational speed sensor a ufweisen, which is intended, in particular to continuously detect a rotational speed of the fluid pump. This advantageously eliminates the need to use flow meters, which can advantageously reduce system costs and / or maintenance costs.

In addition, a method for operating a heater device is proposed, wherein an air ratio of combustion is determined by means of an input power and an ionization current. By using the input power and the ionization current, an advantageously reliable and / or exact determination of the air ratio over a whole power range of a heater, in particular a power-modulating, air-number-controlled gas fan burner, can be made possible. Furthermore, an optimized combustion with a stable heating flame, a minimum pollutant emission and / or a maximum efficiency can advantageously be achieved. be ensured, which in particular a reliability can be increased.

The heater device according to the invention should not be limited to the above-described application and embodiment. In particular, in order to fulfill a mode of operation described herein, the heater device according to the invention may have a number deviating from a number of individual elements, components and units specified herein.

drawing

Further advantages emerge from the following description of the drawing. In the drawing, an embodiment of the invention is shown. The drawing, the description and the claims contain numerous features in combination. Of the

A person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Show it:

1 is a schematic block diagram of a heater designed as a water heater with a heater device,

FIG. 2 is a block diagram for an exemplary operation of the heater apparatus and FIG

3 shows schematically exemplary courses of an ionization current / at three different air ratios A _c as a function of an input power Ρ, _η .

Description of the embodiment

FIG. 1 shows an exemplary heater 22 in a schematic block diagram representation. The heater 22 is formed in the present case as a water heater. Alternatively, it is conceivable that a heater is designed as a storage heater. The heater 22 includes a heater device 10. The heater apparatus 10 includes a heating unit 24. The heating unit 24 is provided to heat a fluid. In the present case, the heating unit 24 is intended to heat water. For this purpose, the heating unit 24 comprises a heating module 26. The heating module 26 is designed as a power-modulating, air-number-controlled gas blower burner module. Alternatively, however, it is also conceivable that a heating unit is provided to heat another fluid, such as a cryogen and / or a heating medium.

The heating module 26 has a variable speed fan 28 for combustion air. The blower 28 is intended to promote and / or regulate a flow of combustion air. For this purpose, the blower 28 is connected to a first supply line 30 for combustion air. In addition, the heating module 26 has a fuel-throughput variable and electronic fuel valve 32. The fuel valve 32 is provided to promote and / or regulate a flow of fuel. In the present case, the fuel valve 32 is provided to promote and / or regulate a gas. For this purpose, the fuel valve 32 is connected to a second supply line 34 for fuel.

The heating module 26 further includes a main burner 36. The main burner 36 is formed as a gas burner. The main burner 36 is connected via the blower 28 to the first supply line 30 for combustion air. In addition, the main burner 36 is connected via the fuel valve 32 to the second supply line 34 for fuel. The main burner 36 is intended to burn a mixture of a combustion air and a fuel in at least one operating state. The main burner 36 is intended to generate a heating flame. In addition, a heating module may include a pilot burner, which is particularly intended to provide a pilot flame for a main burner. In addition, it is conceivable, for example, to use a spark ignition instead of a pilot burner.

Furthermore, the heating unit 24 comprises a heat exchanger 38. The heat exchanger 38 is arranged in a vicinity of the heating flame. The heat exchanger 38 is designed to transfer thermal energy from the heating module 26 to the fluid. For this purpose, the heat exchanger 38 comprises a supply line 40 for an unheated fluid, in particular water, and an outlet 42 for a heated fluid, in particular water. In addition, the heating unit 24 includes an exhaust gas module 44. The exhaust gas module 44 is formed as a chimney. The exhaust module 44 is intended to remove exhaust gases. For this purpose, the exhaust gas module 44 is connected to an exhaust gas outlet 46.

In addition, the heater device 10 has a supply unit 50. The supply unit 50 is provided to supply the unheated fluid to the heat exchanger 38 and / or the heater 22. For this purpose, the feed unit 50 comprises a fluid inlet 52. The fluid inlet 52 is connected to the feed line 40 of the heat exchanger 38 via a fluid connection.

Furthermore, the heater device 10 has a discharge unit 54. The removal unit 54 is designed to remove the heated fluid from the heat exchanger 38 and / or the heater 22. For this purpose, the removal unit 54 comprises a fluid outlet 56. The fluid outlet 56 is connected to the outlet 42 of the heat exchanger 38 via a further fluid connection.

Furthermore, the heater device 10 has a control and / or regulating unit 12. The control and / or regulating unit 12 is provided to control an operation of the heater device 10. For this purpose, the control and / or regulating unit 12 has an arithmetic unit, a memory unit and an operating program stored in the memory unit, which is intended to be executed by the arithmetic unit. In addition, the control and / or regulating unit 12 is provided to set and / or to provide a requested heating power. For this purpose, the control and / or regulating unit 12 has an electrical connection with the blower 28 and the fuel valve 32. In the present case, the control and / or regulating unit 12 is provided to set the combustion air flow and the fuel flow by means of the blower 28 and the fuel valve 32 independently of each other.

The control and / or regulating unit 12 is provided to determine an air ratio A _{c of} the combustion on the basis of an input power Ρ, _η and an ionization current /. Furthermore, the control and / or regulating unit 12 is provided to set the air ratio A _{c of} the combustion to a desired air ratio Ad.

The equations required for this, which are stored in particular in the memory unit of the control and / or regulating unit 12, are summarized below. while an exemplary operation will now be described with reference to FIG.

The control and / or regulating unit 12 is provided to determine the input power P, _n on the basis of an output power P _ou t and a thermal efficiency η of the heating module 26. The following applies:

The thermal efficiency η can for example be determined experimentally with sufficient accuracy and stored in the memory unit of the control and / or regulating unit 12.

In addition, the control and / or regulating unit 12 is provided, the necessary for determining the input power P, _n output power P _ou t based on a temperature of the fluid, in particular an outlet temperature T _ou t of the fluid and inlet temperature Tin of the fluid, and a fluid flow q _m to determine. Where:

Pout ⁼ C | m 'Cp ^■ (Tout - Tin) (2)

In this case, c _p corresponds to a calorific value of the fluid. The heater device 10 has a first temperature sensor 14, which is provided to detect the inlet temperature (Tin) of the fluid immediately after the fluid inlet 52 and / or immediately before the inlet 40 of the heat exchanger 38. Furthermore, the heater device 10 has a second temperature sensor 48, which is provided to detect the outlet temperature (T _ou t) of the fluid immediately after the outlet 42 of the heat exchanger 38 and / or immediately before the fluid outlet 56. Furthermore, the heater device 10 has at least one flow _meter 18, which is provided to detect the fluid flow q _m . Alternatively or additionally, the control and / or regulating unit 12 is provided to determine the fluid flow q _m on the basis of a performance characteristic value of a fluid pump 20. The power characteristic is formed by a pump speed 60 and / or by an electrical power consumption 62 of the fluid pump 20. The individual operating steps for this purpose are illustrated in FIG. 2 on the basis of an exemplary block diagram, wherein an order of the individual operating steps may at least partially vary.

In an operating step 58, the control and / or regulating unit 12 is provided to determine the fluid flow q _m . To determine the fluid flow q _m , the control and / or regulating unit 12 evaluates measured values detected by the flow _meter 18. Alternatively or additionally, the control and / or regulating unit 12 can determine the fluid flow q _m on the basis of a performance characteristic value of a fluid pump 20. The power characteristic is formed by a pump speed 60 and / or by an electrical power consumption 62 of the fluid pump 20.

In an operating step 64, the control and / or regulating unit 12 is provided, on the basis of the detected by the first temperature sensor 14 input temperature T, _{n of} the fluid, detected by the second temperature sensor 48 output temperature Tout of the fluid and the fluid flow q _m in particular using from equation (2) to determine the output power Pout.

In an operating step 66, the control and / or regulating unit 12 is provided to determine the input power Pin based on the output power P _ou t determined in operating step 64 and the thermal efficiency η, in particular using equation (1).

In an operating step 68, the control and / or regulating unit 12 is provided to determine an air ratio A _{c of} the combustion on the basis of the input power Pin and an ionization current determined in operating step 66. The heater device 10 has at least one ionization probe 16, which is intended to detect the ionization / within a combustion flame.

FIG. 3 schematically shows exemplary courses of the ionization current / at three different air numbers A _c as a function of the input power P, _n . It can be seen that the ionization flow / in a rich mixture range (eg A _c = 1, 1) is greater and drops to a lean mixture range (eg A _c = 1, 3 ... 1, 5). It is noticeable that the ionization current / at a constant air ratio A _c (eg A _c = 1, 3) in a range 70 small input powers P, _n decreases significantly in intensity. In the region 70 of small input powers P, _n , the ionization current / its unambiguous assignment loses to the air ratio A _c . By using the input power Pin ascertained in operating step 66 in addition to the ionization current /, the instantaneous air ratio A can be directly determined by means of the control and / or regulating unit 12 over the entire input power range 72, in particular also in the range 70 of small input powers Ρ, _η _{c are} determined.

Claims

claims

1 . Heater device with at least one control and / or regulating unit (12), which is provided to determine an air ratio (A _c ) of a combustion, characterized in that the control and / or regulating unit (12) is provided in at least an operating state, the air ratio (A _c ) based on an input power (Ρ, _η ) and a lonisationsstrom (/) to determine.

2. Heater device according to claim 1, characterized in that the

Control and / or regulating unit (12) is provided to determine the input power (Ρ, _η ) based on an output power (P ₀ ut) and a thermal efficiency (η).

3. heater device according to claim 2, characterized in that the

Control and / or regulating unit (12) is provided to determine the output power (Pout) based on a temperature (Τ, _η , T _ou t) of a fluid and / or a fluid flow (q _m ).

4. Heater device according to one of the preceding claims, characterized by at least one temperature sensor (14, 48) which is provided to detect an input temperature (Τ, _η ) and / or an output temperature (T _ou t) of the fluid.

Heater device according to one of the preceding claims, characterized by at least one ionization probe (16), which is intended to detect an ionization current (/) within a combustion flame.

Heating device according to one of the preceding claims, characterized by at least one flow _meter (18), which is provided to detect a fluid flow (q _m ).

7. Heater device according to one of the preceding claims, characterized in that the control and / or regulating unit (12) is provided to determine a fluid flow (q _m ) based on at least one performance characteristic of a fluid pump (20).

8. A heater device according to claim 7, characterized in that the power characteristic of a pump speed (60) and / or of an electrical power consumption (62) of the fluid pump (20) is formed.

9. heater, in particular gas blower burner, with at least one heater device (10) according to one of the preceding claims.

10. A method for operating a heater device (10), in particular according to one of claims 1 to 8, characterized in that an air ratio (A _c ) combustion based on an input power (Ρ, _η ) and a lonisationsstrom (/) is determined.