DE10348125A1 - Regulation method for ventilation appliance with pref. stationary regenerator to regulate room humidity, and prevent icing-up - Google Patents

Abstract

The cycle duration of a flow through the regenerator (1) is dependent upon at least one of the following:- room humidity, room temperature, external humidity, and external temperature. The aim of cycle duration adjustment is to influence internal humidity and/or prevent formation of ice, and/or prevention of condensate (6) accumulation and/or heating or cooling of the room (4). The regenerator is positioned at an angle, so that any water steam condensate or melt water can flow into warm (3) or cold sections (2).

Description

State of technology

In ventilation technology, regenerators are used (Reg.) For recovery the heat contained in the room air. With reg also transmit moisture (Recovered) become. The regenerator is shifted into opposite ones Flows through directions: once from the interior to the environment (out; the regenerator takes Warmth of the room air) then from the environment to the interior (in; thereby becomes the outside air warmed by the regenerator). Call the time duration at which the air flows in one direction we measure or length of measure. Usually the cycle lengths are (in and out) the same length because the volume flows in the Room in and out of the room should be the same.

Examples of applications for regenerators:

• - Yourself moving regenerators for heat recovery (e.g. Heidelberg recovery team)
• - Fixed locations Heat recovery regenerators.

Examples of processes with regenerators are called below. Air regenerators can be used in areas of heat and moisture recovery be used:

• - heat recovery in the area of building ventilation (residential buildings, offices, sports halls, stables, Industrial Building, Halls, meeting rooms)
• - heat recovery in the area of passenger cars (rail-bound traffic, cars and trucks with auxiliary heating, camping cars).
• - heat recovery in the area of drying (sewage sludge, Cereals, tobacco, fruits, etc.)
• - dehumidification / cooling in Sorption regenerators (sorption cooling, sorption dehumidification)

Problems to be solved

ventilation systems with heat recovery in Plate heat exchanger have major disadvantages:

• 1. On very cold days it can be indoors become dry, as moist indoor air with dry outside air (with low absolute humidity) is exchanged. The disadvantageous Effects of too dry indoor air on comfort and health are known.
• 2. Falls on very cold days Condensate, which has to be drained or there is icing instead of leaving the ventilation system fails. In the case of icing, heating must be carried out (additional energy expenditure) or the fresh air must be preheated in an earth register, which is considerable Effort and investment costs caused.
• 3. On days in the heating season when there is in the area a little warmer than in the interior, the warm outside air is in the plate heat exchanger cooled. The usable heat The environment is not used because the heat from the outside air is transferred to the exhaust air becomes. reason for that is that the heat recovery rate of the plate heat exchanger cannot be set to 0 without special design effort can.

ventilation systems with regenerators offer the control and process engineering Possibility of to overcome the disadvantages of plate heat exchangers:

• 1. Especially on very cold days when the ambient air is very dry, with regenerators is also a high rewet possible. Investments with regenerators have achieved very high heat recovery rates (80% to over 90%) and allow additionally a transfer the humidity from the exhaust air to the supply air (re-humidification), which is a positive It is possible to influence the interior humidity in winter.
• 2. In the case of an extension the cycle time, condensate can evaporate in the regenerator and ice melted so that there is no condensate accumulation. Sinks the heat recovery rate, but permanent operation at very low temperatures is without additional Effort (heating; earth register) possible.
• 3. If the cycle is set to infinity, the heat recovery is and rewetting 0. In this setting, heat can be brought into the interior (heating mode) if the environment is warmer than the interior and warmth be removed from the interior when the interior is warmer than the environment (cooling operation). heating is for example in basements attached that in spring with the outside air can be heated so that the wall temperatures would last of spring on increased Temperatures (around 22 ° C) to be brought; in summer it does not occur on the basement walls heated in this way more about condensate and Mold. cooling is appropriate at night in summer when the room heat is in the Environment should be brought (night cooling).
• 4. If the regenerator is inclined, this can be ensured accumulating condensate flows to warmer areas and there evaporates or that it is in colder areas flows where it is disposed of.

Ventilation systems with regenerators offer special processes (regulation and installation of the regenerators) to avoid accumulating condensate or ice. The regenerator cannot do this as usual Lich flow horizontally, but for example vertically. If the cold side is below, condensate runs to the cold side and exits the regenerator there. If the warm side of the regenerator is at the bottom, the condensate runs there and is evaporated there. If the clocking is suspended, heat and moisture recovery are zero and there is no condensate.

Description of the invention: Process for regulating the cycle length and to treat condensate accumulation

The following options should be through a controller the cycle length the air flow and / or can be solved by a special arrangement of the regenerator:

• 1. The interior humidity should be regulated if it is meteorologically possible is.
• 2. Permanent accumulation of condensate (accumulation) in the regenerator should be avoided.
• 3. A warming or cooling of the room should be possible if the weather permits.

Under condensate accumulation is here in addition to permanent accumulation of liquid condensate also permanent Icing and solid precipitation through resublimation at temperatures below 0 ° C meant. More permanent across bars Precipitation (accumulation) is to be distinguished from short-term Precipitation within two clock cycles, by entering cold air that warms up on the regenerator is removed becomes.

Condensate accumulation can take place within the regenerator. Coupled heat and moisture simulations show the location at which condensate fails and accumulates (accumulates): at locations within the regenerator and not in the coldest area of the regenerator. In 3 is an example of where condensate accumulation begins. The position of the beginning accumulation at the cycle is determined by the dew point of the room air (the temperature of the reg. Must be lower than the dew point) and at the cycle by the drying of the incoming outside air, which initially heats up at the reg. And thereby increases condensate from the government.

The cycle length determines the heat recovery rate and the rewetting of the air. Large cycle lengths mean low rewetting and low heat recovery (with long cycle lengths, the reg. Is dried from the room air, accumulation can be avoided entirely). With increasing cycle lengths, the rewetting drops faster than the heat recovery rate (see 2 , Results from a simulation program with simulation of the coupled heat and moisture transfer).

The claims contain the mentioned methods (Regulation according to the invention the cycle length and installation of the regenerators) as well as the ventilation systems in which the mentioned methods are used, as well as controllers in which the are implemented.

The problem areas mentioned in chapter 2 are solved according to the invention with a method for controlling or regulating the cycle length according to claim 1. The cycle length is determined according to the invention from one or more of the following input variables: interior humidity, interior temperature, ambient humidity and ambient temperature and measured condensate precipitation. The cycle length is controlled from a map so that no condensate accumulates, no ice forms, the interior humidity is affected or heated or cooled. The cycle length is determined from simulations or tests, or is obtained from simultaneous measurements. Claim 2 relates to the installation of the regenerator: the regenerator is inclined, in the best case installed vertically, so that accumulating condensate tends, in the best case installed vertically, so that accumulating condensate or melted melt melted by the control flow to other areas of the regenerator due to gravity in which the water evaporates or emerges from the regenerator (see 3 ).

Claim 3 describes a method for inclined installation of the regenerator, the Reg. in winter is cold above and warm below. Accumulating condensate then runs down into warmer Areas where it evaporates and essentially the interior again supplied becomes. The structure of claim 3 thus means maximization the rewetting and is suitable if possible high indoor humidity levels are aimed for.

Claim 4 describes a method for inclined installation of the regenerator, the Reg. in winter is warm at the top and cold at the bottom. Accumulating condensate then runs in colder Areas where it partially evaporates but essentially from the Device emerges. The structure according to claim 4 means minimizing the rewetting and is suitable if low indoor humidity is desired or the interior should be dehumidified (e.g. in ventilation systems in damp rooms or in greenhouses in those sewage sludge is dried).

Claim 5 and claim 6 show a method in the event that ice occurs in the region which cannot flow into other areas. In these cases, the condensate must be thawed, which requires a temperature in the regenerator of at least 0 ° C. The flowing air, the temperature of which is measured and transferred to the control system, must be warmer than the regenerator, i.e. significantly above 0 ° C, eg 3 ° C. An extraordinary cycle for defrosting only has to be carried out after certain time intervals, for example every 30 minutes. That way it sinks the average heat recovery rate does not decrease very much and accumulating condensate is avoided.

Claim 7 includes a method to regulate the cycle length after the interior humidity. In principle, that applies to high indoor humidity longer Cycle times and shorter cycle times are required if the interior humidity is low are. The cycle time is growing for example monotonous with the interior humidity. There is none strict monotony is required (multi-point controllers are also possible). An example is a p controller in which the cycle length is linear with the interior humidity increases. With such a controller, at low indoor humidity stronger humidified and less or not humidified in high indoor humidity. The interior humidity is measured using the above procedure if meteorological possible, kept in a setpoint range (e.g. between 35 and 70% RH).

Claim 8 includes a method to regulate the cycle length to avoid condensate accumulation. The beat is getting longer continued until the rel. Humidity of the exiting air a maximum value falls below or a linear sensor in the regenerator reports that there is no more condensate. This ensures that the Condensate that accumulated in the previous bar completely failed the regenerator has been removed. There would still be residues of condensate in the regenerator, so would the outflowing Air take up the condensate and a rel. Reach humidity close to 100% or else the linear sensor would Report condensate. With a simple electronic circuit (on- Down counter) the measured cycle time of the cycle to the next cycle be transmitted in. Linear sensor is a sensor that is located inside the regenerator extends from the cold side to the warm side and on this route converts any accumulation of condensate into an electrical signal. The sensor can e.g. be a resistance that depends on moisture however changes regardless of temperature. The Regulation according to claim 8 means low rewetting.

Claim 9 includes a method to regulate the cycle length to avoid condensate accumulation, but with maximization the rewetting. The length the measure in is measured and transferred to the next measure. Measure in starts after the previous measure and ends when the linear sensor reports the drying of the condensate in the regenerator, or if the absolute humidity of the incoming air to the ambient humidity has dropped. In both cases the condensate became complete evaporated and carried into the interior. The rewetting and rewarming number will be maximized because the minimum cycle time is achieved without condensate accumulation.

Claim 10 contains a statement about the Priority of the “Regulation the interior humidity "and" avoidance of condensate accumulation ". Prevention of condensate accumulation is given priority because they condition for the trouble-free Operation of the ventilation system is. That the bar length must not be shorter be than the bar length that is determined in claim 8 or 9.

Claim 11 includes a method to stabilize the regulation of the cycle length. It will be minimal and maximum cycle times, suitable attenuators and delay elements implemented in the scheme to avoid the scheme becomes unstable.

Claim 12 includes a special case the procedure for regulating the clock. In doing so, the cycle length increases infinite (∞) set, which means that the clocking is interrupted. The heat recovery rate and rewetting is then 0. This operation is suitable when the ambient temperature is bigger than the interior temperature and can and should be heated (heating mode) and / or if the interior is to be dehumidified (e.g. heating in Basement, cellar). With this regulation of the cycle, it is possible to reduce the heat consumption buildings further reduce and the formation of condensate in rooms, e.g. Basements too prevent. This in turn makes it possible to avoid the formation of mold.

Claim 13 contains a special case the procedure for regulating the clock. In doing so, the cycle length increases infinite (∞) set, which means that the clocking is interrupted. When the temperature level of the environment is lower than that of the Indoor air becomes an air change without heat recovery (without clocking) set. warmth is brought into the environment from the interior (night cooling operation).

1 shows an example of a regulation stored in the controller for a ventilation unit with regenerators. The rule extends to all normally occurring seasons or temperature conditions in the interior and in the area. With the controller shown, the residents' influence is minimal.

2 shows an example of a dependency of the cycle time on the interior humidity stored in the controller. Low humidity means a short cycle and high rewetting. High humidity means a long cycle and low rewetting.

3 shows an example of a dependence of the volume flow on the interior humidity. Humidity below a threshold value means that no one is present or should not be dehumidified. The ventilation unit remains off. Increasing humidity means that people are present or there is a moisture load. The target volume flow increases.

4 shows the area in the regenerator ( 1 ) on the condensate ( 2 ) occurs and accumulates. The temperature ( 3 ) in the regenerator drops from the warm side (left in the picture) to the cold side (right in the picture). Condensation begins in the figure to the right of the place where the dew point temperature ( 4 ) is undercut.

5 shows the heat and moisture recovery over the cycle length. The moisture recovery sinks faster than the heat recovery. The moisture recovery essentially depends on the ambient conditions. For example, there is no moisture recovery if the ambient temperature is above the dew point temperature of the interior humidity.

6 shows a regenerator inclined by 90 ° ( 1 ). The regenerator ( 1 ) is cold at the top ( 2 ) and warm below ( 3 ). The lower part of the reg. ( 1 ) stands with the interior ( 4 ) in contact. The upper part stands with the environment ( 5 ) in contact. Condensate ( 6 ) moves towards the warm part ( 3 ) of the regenerator ( 1 ) and is vaporized there.

Claims (13)

Method on a ventilation device with at least one preferably stationary regenerator, characterized in that the cycle length of the flow through the regenerator depends on at least one of the variables indoor humidity, indoor temperature, outdoor humidity and outdoor temperature, the aim of setting the cycle length influencing the indoor humidity and / or the Avoiding ice formation and / or avoiding condensate accumulation and / or heating or cooling the interior. Method on a ventilation device with at least one preferably stationary regenerator according to claim 1, characterized in that the regenerator is set up at an incline so that any Steam condensate or melt water in warm areas or in cold areas drain away can. Method on a ventilation device with at least one preferably Fixed regenerator according to claim 1 or 2, characterized in that at least one regenerator is inclined so that the warmer room facing end of the regenerator (s) is lower than that the colder Room associated end, so that the condensate in the warmer room remains and maximum moisture recovery is achieved. Method on a ventilation device with at least one preferably Fixed regenerator according to claim 1 or 2, characterized in that at least one regenerator is inclined so that the warmer room facing end of the regenerator (s) is higher than that of the colder room associated end so that the condensate flows to the colder space and one minimal moisture recovery is achieved. Method on a ventilation device with at least one preferably Fixed regenerator according to claim 1 to 4, characterized in that at outside temperatures below 0 ° C two extraordinary long measures are provided, these measures at certain intervals, z. B. at intervals of one hour, and the Length of extraordinary Measures is selected at least as large, that the cold side of the regenerator during the extraordinary Cycle at which the air flows into the environment at a temperature of at least Reached 0 ° C, the time from the start of the extraordinary bar to to reach 0 ° C is measured and the length the following second extraordinary Is preferably the measured time. Method on a ventilation device with at least one preferably Fixed regenerator according to claim 1 to 4, characterized in that at outside temperatures below 0 ° C two extraordinary long measures are provided, these measures at certain intervals, z. B. at intervals of one hour, and the Length of extraordinary Measures is selected at least as large, that the cold side of the regenerator during the extraordinary Cycle at which the air flows into the environment at a temperature of at least M ° C reached the time from the start of the extraordinary bar to to reach the M ° C is measured and the length the following second extraordinary Is preferably the measured time. Method on a ventilation device with at least one preferably Fixed regenerator according to claim 1 to 6, characterized in that the bar length grows monotonously with the interior humidity. Method on a ventilation device with at least one preferably Fixed regenerator according to claim 1 to 7, characterized in that the bar length is set by a controller so that condensate accumulation is avoided, the cycle length of the beat is taken in from the bar length of the previous bar, this bar at the end of the preceding bar starts in and then ends when the Air leaving the regenerator has a predetermined maximum value falls below relative humidity or a linear sensor reports that there is no condensate inside the regenerator anymore the total amount of condensate has evaporated into the environment. Method on a ventilation device with at least one preferably stationary regenerator according to claim 1 to 7, characterized in that the cycle length is set by a controller condensate accumulation is avoided, the cycle length of the cycle being taken over from the cycle length of the previous cycle, with the cycle beginning at the end of the previous cycle and ending when a linear sensor reports the complete evaporation of the condensate or a humidity sensor reports the condition that the absolute humidity of the air entering the interior has dropped to the absolute humidity of the outside air, i.e. the total amount of condensate has evaporated into the interior. Method on a ventilation device with at least one preferably Fixed regenerator according to claim 1 to 9, characterized in that the controller sets the cycle time as the maximum of the determined cycle times determined from the two control strategies, the control strategies the following are: first, the regulation of the cycle time for optimization the humidity in the interior, as shown in claim 7, and second the regulation of the cycle time to avoid condensate accumulation, as in the claims 8 and 9. Process on a ventilation unit with at least one regenerator according to claims 1 to 10, characterized in that suitable limitations the cycle time, attenuators; P, I and D terms and delay terms be implemented in the scheme. Process on a ventilation unit with at least one regenerator according to claim 1 to 11, characterized in that the timing is interrupted, the direction of air flow in the regenerators is maintained when the temperature conditions in the environment and suitable for heating or drying the interior, heating is then possible is when the ambient temperature is higher than the temperature indoor air and drying is possible when the absolute The humidity of the ambient air is lower than that of the room air. Process on a ventilation unit with at least one regenerator according to claim 1 to 11, characterized in that the timing is interrupted when the ambient air is cooler than the room air and the interior cooled where the space e.g. should then be cooled when the room temperature a limit, e.g. Exceeds 22 ° C.