NL2012681B1

NL2012681B1 - Air handling system, air handling method and building.

Info

Publication number: NL2012681B1
Application number: NL2012681A
Authority: NL
Inventors: Johanna Maria Timmers Stephanus
Original assignee: Deerns Raadgevende Ingenieurs B V
Priority date: 2014-04-24
Filing date: 2014-04-24
Publication date: 2016-07-04
Also published as: WO2015163762A1; NL2012681A

Abstract

The invention relates to an air handling system for providing air to a building, comprising a housing defining an air supply path along which air is able to enter the building and an air exhaust path along which air is able to leave the building, a heat recovery wheel positioned within the air supply path and the air exhaust path to transfer heat between the air supply path and the air exhaust path, an adiabatic humidifier positioned downstream of the heat recovery wheel for humidifying the air, and a control system to control the temperature and the humidity of air entering the building at the same time, wherein in case an available heat transfer capacity of the heat recovery wheel is insufficient to control both the temperature and the humidity at the same time, priority is give to the temperature control by appropriately adjusting the control of the adiabatic humidifier.

Description

Title: Air handling system, air handling method and building

The invention relates to an air handling system, an air handling method and a building comprising such an air handling system.

Air handling systems are known to provide air to a building, wherein the air preferably has desired properties enabling a comfortable environment for the people or equipment inside the building. The most relevant properties of air in a building are the temperature of the air and the humidity of the air.

Known air handling systems may comprise a housing and/or structure defining an air supply path along which air is able to enter the building and an air exhaust path along which air is able to leave the building. When no measures are taken, the air leaving the building usually has a relatively high temperature due to heating of the air inside the building caused by people and equipment. Hence, when the air leaves the building also a lot of energy leaves the building while at the same time the air entering the building usually requires energy to be brought to the desired temperature level. As this is not very efficient, heat recovery systems are commonly applied in air handling systems. A preferred heat recovery system comprises a heat recovery wheel. A heat recovery wheel is positioned within the air supply path and the air exhaust path and normally comprises a circular honeycomb matrix of heat-absorbing material, which is rotated within the air supply path and the air exhaust path of the air handling system. As the heat recovery wheel is rotated, heat or heat and moist is picked up from the air in the air exhaust path in one half of the rotation and given up to the air in the air supply path in the other half of the rotation. Thus waste heat and moist from the air in the air exhaust path is transferred to the matrix material and then from the matrix material to the air in the air supply path, thereby raising the temperature and humidity of the air in the air supply path by an amount proportional to the temperature differential between the air in the air supply path and the air in the air exhaust path and depending upon the efficiency of the heat recovery wheel. The principle also works in reverse if the temperature differential allows, so that the temperature of the air in the air supply path may also be lowered when possible and desired.

In the prior art, in order to control the temperature of air in the building, the heat recovery wheel is controlled based on a predetermined desired temperature in the building, so that a temperature measurement system is present for measuring a temperature of the air and to provide this measured temperature to a control system controlling the heat recovery wheel.

In order to increase the humidity of air in the building, the air handling system may comprise an adiabatic humidifier positioned in the air supply path, which adiabatic humidifier is controlled based on a predetermined desired humidity in the building, so that a humidity measurement system is present for measuring a humidity of the air and to provide this measured humidity to a control system controlling the adiabatic humidifier.

With an adiabatic humidifier water is finely atomised and introduced into the environment. Subsequent vaporisation of the water increases the humidity of the air. Vaporizing the water requires energy In an adiabatic process, this is supplied by the air itself, so that the air is consequently cooled, i.e. lowered in temperature. To compensate for the lowering in temperature, i.e. the temperature drop, a separate additional heater is provided in the prior art. The advantage of this configuration is that temperature and humidity are controlled separately which keeps the required control schemes simple and that the predetermined desired temperature and the predetermined desired humidity can be met.

However, although the prior art air handling systems provide advantages in the form of simple control schemes, they also have difficulty to meet the ever increasing demands with respect to energy consumption and sustainability.

Hence, it is an object of the invention to provide an improved air handling system.

According to the invention, the object is achieved by providing an air handling system according to the preamble of claim 1, characterized in that in normal operation mode of the control system, the control system is further configured such that in case an available heat transfer capacity of the heat recovery wheel is insufficient to control both the temperature and humidity to be at the respective predetermined desired value at the same time, priority is given by the control system to the control of the temperature of the air by appropriately adjusting the control of the adiabatic humidifier.

The invention is based on the insight that the energy consumption of any additional heater used to compensate for a temperature drop caused by the adiabatic humidifier can be saved by using an overcapacity of the heat recovery wheel. As the overcapacity of the heat recovery wheel is not infinite, the adjusted control of the adiabatic humidifier is required in case both the temperature and humidity cannot be optimally controlled at the same time.

In an embodiment, the available heat transfer capacity of the heat recovery wheel is chosen such that without additional heater, the temperature and humidity of the air can be simultaneously controlled to be at their respective predetermined desired values for at least 80% of the time, preferably at least 85% of the time, more preferably at least 90% of the time, and most preferably at least 95% of the time. This means in practice that the heat recovery wheel will be dimensioned larger than in case the heat recovery wheel is optimized for the desired temperature of the air alone without taking into account temperature effects caused by humidifying the air. Dimensioning larger may be implemented by a larger diameter, a higher density of the matrix or an increased thickness of the heat recovery wheel.

As a consequence, the fact that the desired humidity level of the air is not always met is accepted in this embodiment. An advantage thereof is that no special measures such as additional heating of the air by an additional heater need to be taken to meet the desired humidity level in all situations, which measures are relatively expensive and inefficiently used due to the fact that not meeting the desired humidity level will only happen in a minority of the situations, e.g. in extreme outside weather conditions.

The control system may receive the measured temperature and the measured humidity from temperature and humidity measurement systems that are not part of the air handling system, but are arranged externally, e.g. as part of the building. However, the temperature measurement system and/or the humidity measurement system may also be part of the air handling system to measure respectively temperature and humidity in the air supply path and/or air exhaust path. It is also envisaged that the control system receives some measurement signals from externally arranged sensors and other measurement signals from sensors arranged within the air handling system, so that the temperature measurement system and/or the humidity measurement system are not entirely part of the air handling system.

It is to be noted here that where reference is made to a temperature of air in the building and a humidity of air in the building, this also includes the temperature of air and the humidity of air in the air handling system as the air handling system is considered to become part of the building or is at least connected thereto after its installation.

In an embodiment, the temperature measurement system comprises a first temperature sensor arranged downstream of the adiabatic humidifier and/or a second temperature sensor arranged downstream of the heat recovery wheel and upstream of the adiabatic humidifier.

In an embodiment, the humidity measurement system comprises a first humidity sensor arranged downstream of the adiabatic humidifier and/or a second humidity sensor arranged downstream of the heat recovery wheel and upstream of the adiabatic humidifier.

In an embodiment, the control system is configured to also control the heat recovery wheel based on a measured humidity of air in the building provided by the humidity measurement system.

In an embodiment, the control system is configured to also control the adiabatic humidifier based on a measured temperature of air in the building provided by the temperature measurement system.

In an embodiment, the air handling system further comprises an additional heater positioned in the air supply path to provide heat to air in the air supply path, wherein the control system in a start-up mode thereof is configured to increase the temperature of air entering the building by controlling the additional heater based on a measured temperature of air provided by the temperature measurement system.

The additional heater can thus advantageously be used in case the temperature difference between the air leaving the building and the air entering the building is too small for the heat recovery wheel to function properly. This may occur during a start-up of the system, but may also occur when the predetermined desired values for the temperature and/or humidity are changed and the system needs to adapt itself to the changing control settings.

In an embodiment, the air handling system further comprises one or more of the following components: - one or more demisters; - one or more air filters; - one or more fans or other air displacement devices; - one or more cooling elements; - one or more heaters; and - one or more silencers.

The invention also relates to an air handling method for providing air to a building, wherein use is made of an air handling system comprising an air supply path along which air is able to enter the building, an air exhaust path along which air is able to leave the building, a heat recovery wheel to transfer heat between air in the air supply path and air in the air exhaust path, and an adiabatic humidifier to humidify air in the air supply path, said method comprising the following steps: i. controlling a temperature of air entering the building to be at a predetermined desired value by controlling the transfer of heat by the heat recovery wheel based on a measured temperature of the air; ii. controlling a humidity of air entering the building to be at a predetermined desired value by controlling the adiabatic humidifier based on a measured humidity of the air; iii. determining whether an available heat transfer capacity of the heat recovery wheel is sufficient to control the temperature and humidity of the air entering the building to be at their respective predetermined desired values at the same time; and iv. in case the available heat transfer capacity of the heat recovery wheel is insufficient to control both the temperature and humidity to be at their respective predetermined desired values at the same time, the control of the adiabatic humidifier is adjusted to give priority to the control of the temperature of the air.

In an embodiment, available heat transfer capacity of the heat recovery wheel is chosen such that without additional heater, the temperature and humidity of the air can be simultaneously controlled to be at their respective predetermined desired values for at least 80% of the time, preferably at least 85% of the time, more preferably at least 90% of the time, and most preferably at least 95% of the time.

In an embodiment, the method also comprises the following steps: - measuring a temperature of the air; - measuring a humidity of the air; and - controlling the transfer of heat by the heat recovery wheel based on the measured temperature and based on the measured humidity.

In an embodiment, the method also comprises the following steps: - measuring a temperature of the air; - measuring a humidity of the air; and - controlling the adiabatic humidifier based on the measured temperature and based on the measured humidity.

In an embodiment, the steps are carried out in a normal operation mode of the air handling system, and wherein the air handling method system further comprises a start-up mode in which the following step is carried out: - controlling a temperature of air entering the building to be at a predetermined desired value by controlling an additional heater in the air supply path based on a measured temperature of the air.

Temporarily controlling the temperature of the air using an additional heater can advantageously be used in case the temperature difference between the air leaving the building and the air entering the building is too small for the heat recovery wheel to function properly. This may occur during a start-up of the system, but may also occur when the predetermined desired values for the temperature and/or humidity are changed and the system needs to adapt itself to the changing control settings.

The invention further relates to a building comprising an air handling system according to the invention.

The invention will now be described in a non-limiting way by reference to the accompanying drawings in which like parts are indicated by like reference symbols, and in which:

Fig. 1 depicts an embodiment of an air handling system according to the invention;

Fig. 2 depicts an embodiment of a control system for a first configuration of the air handling system of Fig. 1;

Fig. 3 depicts an embodiment of a control system for a second configuration of the air handling system of Fig. 1; and

Fig. 4 depicts an embodiment of a control system for a third configuration of the air handling system of Fig. 1.

Fig. 1 depicts an embodiment of an air handling system according to the invention. In Fig. 1, the air handling system is shown schematically in cross sectional view. The air handling system comprises a housing HO including two outer walls OW1, OW2 and an inner wall IW. The housing defines an air supply path ASP along which air is able to enter a building BU which is located in this embodiment on the right side of the air handling system. Usually the air is drawn from outside the building. The environment EN of the building is in this embodiment depicted on the left side of the drawing. Hence, the air flow from environment EN to building BU is in this embodiment from left to right via the air supply path ASP as indicated by arrows A1.

The housing further defines an air exhaust path AEP separated from the air supply path ASP by the inner wall IW along which air is able to leave the building BU. Usually the air is dumped in the environment EN. Hence, the air flow from the building BU to the environment is in this embodiment from right to left via the air exhaust path AEP as indicated by arrows A2.

In this embodiment, air is forced through the air supply path ASP via a fan V1 and air is forced through the air exhaust path AEP via a fan V2, but the fans may be replaced by any other suitable air displacement device.

In order to recover heat from the air flowing in the air exhaust path and leaving the building, a heat recovery wheel HRW is positioned within the air supply path ASP and the air exhaust path AEP to transfer heat between air in the air supply path ASP and air in the air exhaust path AEP.

The heat recovery wheel HRW may comprise a circular honeycomb matrix of heat-absorbing material, which is rotated within the air supply path and the air exhaust path of the air handling system. Rotation of the heat recovery wheel about an axle AX is in this embodiment carried out using a motor MO. As the heat recovery wheel is rotated, heat and possibly moist is picked up from the air in the air exhaust path in one half of the rotation and given up to the air in the air supply path in the other half of the rotation. Thus waste heat and possibly moisture from the air in the air exhaust path is transferred to the matrix material and then from the matrix material to the air in the air supply path, thereby raising the temperature and possibly the humidity of the air in the air supply path by an amount proportional to the temperature differential between the air in the air supply path and the air in the air exhaust path and depending upon the efficiency of the heat recovery wheel.

The principle also works in reverse if the temperature differential allows, so that the temperature of the air in the air supply path may be lowered when possible and desired. As a result, although the main purpose of the heat recovery wheel is to recover heat from the air leaving the building, it is also possible in certain circumstances to transfer heat from air in the air supply path to air in the air exhaust path. Hence, in these circumstances the air entering the air handling system is cooled first by the heat recovery wheel before being supplied to the building and the heat is dumped in the air exhaust path and subsequently provided to the environment EN.

The air handling system further comprises in this embodiment filters FI arranged at the respective beginnings of the air supply path ASP and the air exhaust path AEP.

The air handling system further comprises an adiabatic humidifier AH positioned in the air supply path ASP downstream of the heat recovery wheel HRW for humidifying air entering the building BU.

With the adiabatic humidifier water is finely atomised and introduced into the air supply path ASP. Subsequent vaporisation of the water increases the humidity of the air. Vaporizing the water requires energy. In an adiabatic process this is supplied by the air itself, so that the air is consequently cooled, i.e. lowered in temperature. The lowering in temperature caused by the adiabatic humidifier is referred to as temperature drop.

In prior art air handling systems the solution is to add a separate heater in between the heat recovery wheel and the adiabatic humidifier, so that the heater is capable of compensating the temperature drop caused by the adiabatic heater. This solution is obvious as it maintains the advantage of separate easy control schemes for the respective heat recovery wheel and the adiabatic humidifier and does not require changes to the measurement system. The temperature and humidity may be measured downstream of the adiabatic humidifier. For instance, when controlling the adiabatic humidifier, it is known or can be determined how the adiabatic humidifier is functioning. As a consequence the temperature drop caused by the adiabatic humidifier can be determined or estimated based on the operation of the adiabatic humidifier itself. With this information, the additional separate heater can easily be controlled to compensate for the temperature drop without having to measure the temperature or temperature drop directly.

It is explicitly noted here that in the prior art the adiabatic humidifier is controlled based on a measured humidity. Hence, the associated controller comprises a single input and provides an output signal to the adiabatic humidifier and an output signal to the separate heater. The heat recovery wheel in turn is controlled based on a measured temperature. Hence, the associated controller comprises a single input and provides a single output to the heat recovery wheel.

However, a disadvantage of this prior art solution is that the operational costs of the additional separate heater for humidification are relatively high.

The air handling system comprises a control system CS to control the temperature and humidity of air entering the building by controlling the heat recovery wheel and adiabatic humidifier. In a normal operation mode of the control system, the control system is configured to control a temperature of air entering the building to be at a predetermined desired value by controlling the transfer of heat by the heat recovery wheel based on a measured temperature of the air provided by a temperature measurement system, and to control a humidity of air entering the building to be at a predetermined desired value by controlling the adiabatic humidifier based on a measured humidity of air provided by a humidity measurement system.

According to the invention, the control system, in the normal operation mode thereof, is further configured such that in case an available heat transfer capacity of the heat recovery wheel is insufficient to control both the temperature and humidity to be at the respective predetermined desired values at the same time, priority is given by the control system to the control of the temperature of the air by appropriately adjusting the control of the adiabatic humidifier.

An advantage thereof is that no additional heater is used during humidification, which lowers the operational costs. The consequence is that it is accepted that the desired humidity level is not met in all circumstances.

To implement this control configuration many alternatives exist. A few of them will be described below by reference to Fig. 1.

In the embodiment of Fig. 1 it is assumed that the air handling system comprises a temperature measurement system to measure a temperature of the air, in this case the temperature of air in the air supply path, and a humidity measurement system to measure a humidity of the air, in this case the humidity of air in the air supply path.

The humidity measurement system may therefore comprise a first humidity sensor HS1 positioned downstream of the adiabatic humidifier to measure a humidity of air. The humidity measurement system may further comprise a second humidity sensor HS2 positioned downstream of the heat recovery wheel HRW and upstream of the adiabatic humidifier AH.

The temperature measurement system may therefore comprise a first temperature sensor TS1 positioned downstream of the adiabatic humidifier AH and/or a second temperature sensor TS2 positioneel downstream of the heat recovery wheel HRW and upstream of the adiabatic humidifier AH.

The first and second temperature sensors, when present, provide a first temperature signal TSI1 and second temperature signal TSI2, respectively, to the control system CS. The first and second humidity sensors, when present, provide a first humidity signal HSI1 and second humidity signal HSI2, respectively, to the control system CS.

The control system outputs a control signal ASI to the adiabatic humidifier AH, a control signal WSI to the motor MO of the heat recovery wheel HRW, a control signal VS1 to the fan V1 and a control signal VS2 to the fan V2.

First configuration:

In a first configuration, the temperature measurement system comprises only the first temperature sensor TS1 and the humidity measurement system only comprises the first humidity sensor HS1.

By using a temperature sensor downstream of the adiabatic humidifier as input for the temperature control by the heat recovery wheel, the temperature drop caused by the adiabatic humidifier is automatically included in the measured temperature and thus the control of the heat recovery wheel will automatically try to compensate for the temperature drop caused by the adiabatic humidifier.

An example thereof is shown in Fig. 3. Fig. 3 depicts a control system CS corresponding to the first configuration of the embodiment of Fig. 1. The control system CS comprises a first controller C1 to control the heat recovery wheel and a second controller C2 to control the adiabatic humidifier AH.

Input to the first controller is the first temperature signal TSI1 from the first temperature sensor. Based on the first temperature signal TS11, the first controller outputs a control signal WSI to the motor MO of the heat recovery wheel. It is to be noted that the controller C1 is depicted here as a black box and that the control structure inside the controller C1 may have any configuration, such as P, PI, PD or PID control, possibly including feedback.

Input to the second controller C2 is the first humidity signal HSI1 from the first humidity sensor and the first temperature signal TSI1 from the first temperature sensor. The second controller outputs a control signal ASI to the adiabatic humidifier.

By providing the first temperature signal to the second controller, the control system is able to determine whether the available heat transfer capacity of the heat recovery wheel is sufficient to compensate for the temperature drop caused by the adiabatic humidifier and thus whether both the temperature and humidity of the air can be controlled to be at the respective predetermined desired values at the same time. The second controller is then configured such that in case the available heat transfer capacity of the heat recovery wheel is insufficient to control both the temperature and humidity to be at the respective predetermined desired values at the same time, priority is given by the control system, i.e. the second controller, to the control of the temperature of the air by appropriately adjusting the control of the adiabatic humidifier.

Second configuration:

In a second configuration, the temperature measurement system comprises the first temperature sensor TS1 and the second temperature sensor TS2, and the humidity measurement system comprises the first humidity sensor HS1 and the second humidity sensor HS2.

An example of a control system according to the second configuration is shown in Fig. 3.

Fig. 3 depicts a control system CS corresponding to the second configuration of the embodiment of Fig. 1. The control system comprises a first controller C1 to control the heat recovery wheel and a second controller C2 to control the adiabatic humidifier AH.

Input to the first controller C1 is the second temperature signal TSI2 from the second temperature sensor and the second humidity signal HSI2 from the second humidity sensor. Based on the second temperature signal and the second humidity signal, the first controller is able to determine the heat required to bring the temperature of air to the desired level and to determine the temperature drop caused by the adiabatic humidifier to bring the humidity of the air to the desired level. The first controller is then able to determine the control signal WSI to be send to the motor MO of the heat recovery wheel.

Hence, the first controller controls the heat recovery wheel to get the most out of the heat recovery wheel, but is limited by the maximum available heat transfer capacity.

Input to the second controller C2 is the first humidity signal HSI1 from the first humidity sensor and the first temperature signal TSI1 from the first temperature sensor. The second controller C2 outputs a control signal ASI to be provided to the adiabatic humidifier, which control signal ASI is based on both the first humidity signal and the first temperature signal. The first humidity signal can be used to determine the amount of humidification in order to bring the humidity of the air to the desired level. By providing the first temperature signal to the second controller, the second controller is able to determine whether the heat recovery wheel is able to compensate for the temperature drop and thus if the air entering the building will have the desired temperature after being humidified by the adiabatic humidifier. In case the temperature of the air entering the building is below a predetermined desired level, the second controller is able to adjust the control of the adiabatic humidifier such that the introduced temperature drop is reduced to an acceptable level that can be compensated by the heat recovery wheel.

Hence, the second controller controls the adiabatic humidifier to get the desired humidity of the air, but is limited by the minimally required temperature of the air.

Third configuration:

In a third configuration, the temperature measurement system only comprises the second temperature sensor TS2 and the humidity measurement system only comprises the first humidity sensor HS1.

An example of a control system according to the third configuration is shown in Fig. 4. Fig. 4 depicts a control system CS corresponding to the third configuration of the embodiment of Fig. 1. The control system comprises a first controller C! to control the heat recovery wheel and a second controller C2 to control the adiabatic humidifier AH.

Input to the second controller C2 is the first humidity signal HS1 from the first humidity sensor and the second temperature signal TS2 from the second temperature sensor. The second controller outputs a control signal ASI to be provided to the adiabatic humidifier in order to set the humidity to a predetermined desired humidity value. By providing the second temperature signal to the second controller, the second controller is able to determine whether the available heat transfer capacity of the heat recovery wheel is sufficient to control both the temperature and humidity to be at the respective predetermined desired values at the same time. The second controller is further configured such that in case an available heat transfer capacity of the heat recovery wheel is insufficient to control both the temperature and humidity to be at the respective predetermined desired values at the same time, priority is given by the control system to the control of the temperature of the air by appropriately adjusting the control of the adiabatic humidifier.

Input to the first controller is the second temperature signal from the second temperature sensor and the control signal ASI. The first controller is able to determine from the control signal ASI how the adiabatic humidifier is operated and thus what the estimated temperature drop caused by the adiabatic humidifier is. Based on the estimated temperature drop and the second temperature signal, the first controller outputs a control signal WSI to the motor of the heat recovery wheel.

Because the control signal WSI is based on the control signal ASI and the control signal ASI in turn is based on the first humidity signal HS1, the heat recovery wheel is controlled based on the measured temperature of the air and based on the measured humidity of the air. Hence, for the invention it is not relevant whether the dependency on the measured temperature and/or measured humidity of the air is direct or indirect.

The above configurations that have been described relate to the normal operation mode of the air handling system.

In an embodiment of the invention, the air handling system is provided with an additional heater HE as shown in Fig. 1. Although this additional heater is in principle not used during the normal operation mode, this heater HE can advantageously be used during a start-up mode of the system or during very extreme environmental conditions outside the normal operation conditions.

During start-up of the air handling system, the situation may arise in which the air drawn from the building and passing through the air exhaust path AEP is equal or substantially equal in temperature as the air taken in from the environment and passing through the air supply path. As a result, the temperature difference across the heat recovery wheel is not sufficient or even absent for the heat recovery wheel to heat up the air in the building. The control system may in such a case switch to the start-up mode in which the temperature of the air entering the air supply path is raised by the heater HE. Hence, in the shown configurations of figs. 2-4, the first controller will not output a control signal WSI, but instead outputs a control signal HES to the heater HE based on the inputs to the first controller. The control signal HES is shown in Fig. 1 only.

Claims

An air treatment system for providing air to a building, comprising: - a housing that defines an air supply path through which air can enter the building, and which defines an air discharge path through which air can leave the building; - a heat wheel located in the air supply path and in the air discharge path for transferring heat between air in the air supply path and air in the air discharge path; - an adiabatic humidifier located in the air supply path downstream of the heat wheel for humidifying air entering the building; - a control system which in its normal operating mode is arranged to control a temperature of air entering the building to be at a predetermined desired value by controlling the transport of heat through the heat wheel based on a measured temperature of the air supplied by a temperature measurement system, and to control a humidity of air entering the building to be at a predetermined desired value by controlling the adiabatic humidifier based on a measured humidity provided by a humidity measurement system, characterized in that in the normal operating mode of the control system, the control system is further arranged such that in the case an available heat transfer capacity of the heat wheel is insufficient to control both the temperature and the humidity to simultaneously reach their respective predetermined desired values priority is given by r the control system to control the temperature of the air by adjusting the control of the adiabatic humidifier accordingly.

The air treatment system according to claim 1, wherein the available heat capacity of the heat wheel is selected such that without additional heater the temperature and humidity of the air can be controlled simultaneously to be at their respective predetermined values for at least 80% of the time , preferably at least 85% of the time, more preferably at least 90% of the time and even more preferably at least 95% of the time.

The air treatment system according to claim 1 or 2, wherein the temperature measuring system and the humidity measuring system form part of the air treatment system.

The air treatment system according to any of claims 1 to 3, wherein the temperature measurement system comprises a first temperature sensor located downstream of the adiabatic humidifier and / or a second temperature sensor located downstream of the heat wheel and upstream of the adiabatic humidifier is.

The air treatment system according to any of claims 1 to 4, wherein the humidity measurement system comprises a first humidity sensor located downstream of the adiabatic humidifier and / or a second humidity sensor located downstream of the heat wheel and upstream of the adiabatic humidifier .

The air treatment system according to any of claims 1 to 5, wherein the control system is further adapted to control the temperature of air entering the building to be at a predetermined desired value by controlling the transport of heat through the heat wheel based on a measured air humidity provided by the humidity measurement system.

The air treatment system according to any of claims 1 to 6, wherein the control system is further adapted to control the humidity of air entering the building to be at a predetermined desired value by controlling the adiabatic humidifier based on of a measured temperature of air provided by the temperature measurement system.

The air treatment system according to any of claims 1 to 7, further comprising an additional heater located in the air supply path to supply heat to air in the air supply path, wherein the control system in a start-up mode thereof is arranged to control the temperature of air enter the building by controlling the additional heater based on a measured temperature of air provided by the temperature measurement system.

The air treatment system according to any of claims 1 to 8, further comprising one or more of the following components: a dehumidifier, an air filter, a fan, a cooling element, a heater and a silencer.

10. An air treatment method for supplying air to a building, wherein use is made of an air treatment system with an air supply path through which air can enter the building, an air discharge path through which air can leave the building, a heat wheel for transporting heat between air in the air supply path and air in the air discharge path, and an adiabatic humidifier for humidifying air in the air supply path, the method comprising the steps of: controlling a temperature of air entering the building to be at a predetermined desired value by controlling the transport of heat through the heat wheel based on a measured temperature of the air; controlling a humidity of air entering the building to be at a predetermined desired value by controlling the adiabatic humidifier based on a measured humidity; determining whether an available heat transfer capacity of the heat wheel is sufficient to control the temperature and humidity of the air entering the building to be simultaneously at their respective predetermined desired values; and - in case the available heat transfer capacity of the heat wheel is insufficient to control the temperature and humidity of the air to be simultaneously at their respective predetermined desired values, the control of the adiabatic humidifier is adjusted to give priority to control of the temperature of the air.

The air treatment method according to claim 10, wherein the available heat capacity of the heat wheel is selected such that without additional heater the temperature and humidity of the air can be controlled simultaneously to be at their respective predetermined values for at least 80% of the time , preferably at least 85% of the time, more preferably at least 90% of the time and even more preferably at least 95% of the time.

The air treatment method according to claim 10 or 11, further comprising the steps of: measuring a temperature of the air; measuring a humidity of the air; - controlling the transport of heat through the heat wheel on the basis of the measured temperature and on the basis of the measured humidity.

The air treatment method according to any of claims 10 to 12, further comprising the steps of: measuring a temperature of the air; measuring a humidity of the air; controlling the adiabatic humidifier based on the measured temperature and based on the measured humidity.

The air treatment method according to any of claims 10 to 13, wherein the steps are performed in a normal operating mode of the air treatment system, and wherein the air treatment method further comprises a start-up mode in which the following step is performed: controlling a temperature of air entering the building to be at a predetermined desired value by controlling an additional heater in the air supply path based on a measured temperature of the air.

A building comprising an air treatment system according to any of claims 1 to 9.