Applications

How do you calculate the cooling capacity?

The cooling capacity is calculated by changing the energy transferred during the cooling process.
WHAT IS THE COOLING CAPACITY?
Cooling capacity is the amount of energy transferred during a cooling process. Cooling power is measured in joules or watts and can be calculated by calculating the change in energy transferred by the cooling process.

Cooling capacity is an important parameter in evaluating the efficiency of cooling systems and can be used to compare the performance of different systems. A higher cooling capacity value usually means that more energy is provided per time.

HOW IS THE COOLING CAPACITY CALCULATED?

The cooling capacity can be calculated with the following formula:

Q = m * c * ΔT

In this formula:

Q: cooling capacity (in joules or watts)
m: mass of the cooling medium (in kg)
c: specific heat capacity of the cooling medium (in J/kg * K)
ΔT: change in temperature of the cooling medium (in Kelvin).

It is important to note that this formula only applies to isothermal processes where the temperature of the cooling medium remains constant. Other applications require more complex methods to calculate the cooling capacity. We recommend contacting an expert to calculate the cooling capacity for a specific application.

WHAT HAS TO BE CONSIDERED WHEN MIXING HEAT CARRIERS WITH WATER?

In principle, no two different heat transfer media may be mixed together. Only when mixing with water can full frost and corrosion protection still be guaranteed.

Nevertheless, some points should also be observed here. The water must never be added to the heat transfer medium just like that, because there is a risk that TIGSol® is unevenly distributed in the mixture and cannot develop its full effectiveness. Therefore, the mixture must be homogenised in any case until it has a uniform colour. This can be done, for example, by stirring. Only when this step has been carried out successfully can the heat transfer medium / water mixture be used.

Refrigeration optimization and product planning according to electricity spot price. While refrigeration is an energy-intensive process, Digital Twin functionality allow calculate true cooling energy consumption link to production and electricity price also as successfully achieve planned production goals.

EA-SAS Cooling is a Digital Twin and AI based solution designed to reduce electricity consumption through continuous calculation of refrigeration system mass and energy balance, continues COP evaluation also as advanced automatic set points control. EA-SAS Cooling does not require additional investments to infrastructure.

EA-SAS Cooling as a service deliver 24/7 availability of Digital Twin solution without hardware changes and ROI less than 1 year. 

What is the difference between Digital Twin and standard Control system (SCADA)?

Traditional control systems rely on data collection from equipment and PLC control logic, however human is responsible for setpoint decision and change. Digital Twin together with Artificial Intelligent based algorithms deliver setpoints to the PLC instead of operator. Optimized control Setpoints are delivered each minute, instead of humans with hourly delay.

Controlled Atmosphere

By using CA, the physiological processes in the stored product are slowed down, resulting in an extended storage life. The product is put into hibernation so to speak. The required conditions are achieved by creating and maintaining a special protective atmosphere.

Lowering the oxygen level slows respiration and reduces the metabolism of important nutrients. The aim is to keep the oxygen level as low as possible in order to preserve these nutrients – hence quality.

The remaining oxygen is converted into CO2, which in turn ensures that the respiration of fruit and vegetables is further slowed down. However, excess CO2 will damage your product and must therefore be removed.

Ethylene is produced by fruit and vegetables and stimulates the ripening process – hence the ageing process. In order to slow down these processes, it is necessary to remove this harmful ethylene gas from the air of the cold stores for some products.

Each product variety requires different conditions. Depending on factors such as climate, weather, soil conditions, growing conditions and the time of picking, the optimum conditions vary not only year by year, but also from one product to another and even from one variety to another. As experts in CA storage, we offer you tailored solutions and every opportunity to keep a close watch on your valuable produce.

These days, many different storage concepts are available: ULO, DCA, ILOS, DILOS, DCE, etc. Besseling can supply both the protocols and the required equipment for these concepts.

Dynamic Controlled Atmosphere

Low oxygen levels have proved their effectiveness during the storage of fruit and vegetables. The lower the oxygen level, the less the fruits respire and the less they deteriorate in quality. Moreover, disorders like scald can be reduced significantly. There is however a lowest limit to the oxygen level. The lowest possible oxygen level differs dependent on variety, season and the quality of the fresh produce.

Controlled Atmosphere Disinfestation

Insects are a pest for commodities. By decreasing the level of oxygen in a gastight, temperature controlled store a mortality rate of 100% can be achieved. This treatment is lethal, non-toxic and does not have a negative influence on the treated product itself.

Controlled Atmosphere disinfestation is suitable for;

• cacao;
• tobacco;
• soya;
• rice;
• grain;
• and many other commodities.

The efficacy of the treatment is depending on physical factors such as gas concentration, temperature and relative humidity. There are also biological factors such as insect species, strain and development stage. Besseling masters these conditions and can help you in design and implementation of the essential components.
 

Hypoxic Fire Prevention

Fire, the nightmare of every business. There is no sadder sight than the smoldering remains of what used to be your storehouse or archive. Of course you take precautions. You store flammable materials separately and of course you have fire extinguishers to hand.

However, danger is never far away… Unless you remove the most important factor: oxygen. Without oxygen, a fire simply cannot get started. By reducing oxygen to a level at which combustion is impossible – a perfect and proven alternative to sprinkler systems and/or compartmentalization of large storage facilities. Examples are:

• Freezer and cold storage facilities
• Telecommunications and computer rooms
• Storage of hazardous substances such as fireworks, munitions, gas cylinders, etc.
• Archives & museums

The Besseling PSA nitrogen generator combined with a measurement and control system (ACS) is the perfect solution. The measurement and control system also provides the required level of safety thanks to alarms based on thresholds which can be set by the user.

dew point temperature

The dew point temperature is a limit temperature at which the air is 100% saturated with water vapour. At this point, no condensation occurs, nor can the air continue to hold water vapor.

When the temperature is lowered to a lower level, water is eliminated from the air by condensation.

An example is shown in the h,x diagram: If, for example, air with an absolute water content of x = 11 g/kg cools down from 30 °C to + 15 °C, the saturation line is reached.

A further cooling of the air leads to the elimination of condensate. The intersection of a vertical x-line with the saturation line is called the dew point and the corresponding temperature is called the dew point or saturation temperature

At dew point temperatures below the freezing point of water, the term frost or freezing point is also used.

wet bulb temperature

If the measuring tip of a thermometer is moistened, the thermometer shows a lower temperature than the measured room temperature.

How does it work?

The thermometer indicates the so-called wet-bulb temperature.

This can be done with any thermometer by moistening the measuring tip. As soon as the moisture has reached room temperature, it begins to evaporate.

The evaporation process is a phase change that requires latent heat. This energy is extracted from the surrounding air, which cools down and the water cools down with it. The sensible heat of the air decreases due to the evaporation process. However, their latent heat increases to the same extent. The cooling process of the air is therefore adiabatic (heat-tight). Depending on the relative humidity of the air, a lower temperature can be read on the thermometer, the so-called wet-bulb temperature.

The difference between the room temperature and the wet bulb temperature is a measure of the relative humidity.

A calculation example:

At a room temperature of 23°C and a wet bulb temperature of 18°C, the determined relative humidity is φ = 60%.

The wet-bulb temperature is of practical importance for indirect evaporative cooling or for humidifying room air in air-conditioning technology.

air warming

The simplest case of changing the state of air is heating. Water is neither added nor removed from the air (x = constant). However, as the temperature increases while the absolute humidity remains the same, the relative humidity decreases. In the diagram shown it can be seen that the line runs vertically upwards during heating. Heating the air to a desired temperature requires the amount of heat Δh.

In our example we increase the temperature from approx. 15°C to approx. 27°C. This requires a heat quantity of Δh = (h2 - h1) = (47 - 35) = 12 kJ/kg

Air Cooling

Air is cooled on surface coolers such as air coolers or evaporators. Two cases can occur when air is cooled, with the temperature of the surface being decisive. The dew point temperature of the air is above or below the cooler temperature.

Cool air without condensate separation

If the temperature of the cooler surface is above the dew point temperature, no water is separated from the air to be cooled. The absolute proportion of moisture remains constant (x = constant). Accordingly, the relative humidity of the air increases after cooling.

In the h,x diagram, the line runs vertically downwards, parallel to the line with constant water vapor content x.

Air cooling with condensate separation

If the temperature of the cooler surface is below the dew point temperature, water is separated from the air to be cooled

This process is shown in simplified form in the h,x diagram. The line runs from point Θ 1 along the imaginary line to the radiator surface temperature. Depending on the air flow, structure and surface area of ​​the surface cooler, the temperature Θ 2 is set . As a result, the line runs slightly obliquely. This creates a difference of Δx. Through further calculations, it is possible to specify an absolute amount of water with the Δx for a specific period of time for the cooling process. This value is relevant for the design of defrost water pipes and defrost water pumps or lifting systems. The relative humidity increases during the cooling process, but not as much as in the previous example "Cooling the air without condensation occurring".

The state of comfort on the h,x diagram

Absolutely dry air does not occur in our atmosphere. It always contains a certain amount of water vapor. Moist air is therefore a mixture of dry air and an absolute proportion of water vapour. Depending on the temperature, the dry air is able to absorb a different proportion of water. In principle, warm air has a greater absorption capacity than colder air. The relative humidity results from the interaction of absorption capacity and temperature.

About the formula :

the percentage can be calculated or determined using the h,x diagram.

x = amount of steam present in g/kg

x s = amount of vapor in saturated air in g/kg

φ = relative humidity

state of comfort

Depending on the percentage of vapor in the air and the temperature of the air, there are prescribed conditions for each application.

According to DIN 1946, thermal comfort is given when the air temperature, air humidity, air movement and thermal radiation in the environment are perceived as optimal and neither warmer nor colder, drier or damper room air is desired.

DIN EN ISO 7730 defines thermal comfort as a feeling that expresses satisfaction with the ambient climate.

The state of comfort on the h,x diagram

Air and the moisture it contains:

Humidity, moist or dry air, warm or cold air. Everyone can imagine something under these terms and can also tell something about it. We give you an overview of this topic, clear up any errors and use the very helpful tool "hx - diagram" for this.

At this point we would like to thank the Kaut company for providing us with the diagram.

What is the h,x diagram?

h stands for enthalpy - the energy content of a substance in 1 kJ / kg

x stands for water content - the absolute amount of water in g / kg of dry air

The h,x - diagram was developed in 1923 by Richard Mollier. It enables changes in the state of humid air due to heating, humidification, dehumidification or cooling to be clearly displayed. The status changes can be determined graphically directly from the diagram.

It is an important tool for the refrigeration and air conditioning industry. In addition, this diagram can also be very useful for your own 4 walls.

The structure

The X-axis represents the water content x.

The y-axis shows the air temperature in °C.

The partial pressure of the water vapor is given as the second x-axis.

Isenthalpens - Lines of equal specific enthalpy

The isenthalpes are lines of the same specific enthalpy. The lines run steeply downwards. The scaling is shown below the saturation line. The lines are parallel to each other.

The enthalpy h is given in 1kJ/kg.

In the diagram shown, the value range is from 0kJ/kg to 90kJ/kg

Lines of equal absolute humidity

The lines are vertical and parallel to each other. The value is read directly from the X-axis.

Absolute humidity x stated in 1g/kg.

In the diagram shown, the value range is from 0g/kg to 25g/kg

Lines of equal relative humidity

A curved line not parallel to each other.

They are limited with the dew line (1.0 - 100%).

The relative humidity indicates how large the amount of vapor present in the air is in relation to the saturation amount of vapor.

The relative humidity φ is given in 1%.

In the diagram shown, the range of values ​​is from 0% to 100°C.

lines of equal density

The lines of equal density run from left to right with a slight gradient.

The density [RHO] ϱ is specified in 1kg/m 3 .

In the diagram shown, the range of values ​​is from 1.09 kg/m 3  to 1.38 kg/m 3 .

The isotherm - lines of equal temperatures

The lines of equal temperatures run parallel to the x-axis at 0°C.

With increasing temperatures, the lines rise slightly in the course. Below 0°C the lines fall off slightly.

The temperature T is given in 1°C.

In the diagram shown, the value range is from -20°C to +55°C.

Air conditioners for your own home

Air conditions are changed with air conditioning systems. We give a rough overview of the types and functions of air conditioning systems.

Air conditioning systems are used when room air conditions are to be changed. The two most important changes in state are the temperature and the humidity in a room.

An air conditioning system thus influences the room air as follows:

1. Air is cooled
2. Air is heated
3. Air is humidified
4. Air is dehumidified

Basic function

The functional principle of an air conditioning system is that of a classic refrigeration system. Now there are very many types and differences in this area. In this post, however, we will focus on the commercially available systems. Basically, a refrigeration and air conditioning system is used to dissipate heat. Heat is absorbed on one side and heat is given off on the other side. The absorption and release of heat takes place via heat exchangers. The energy exchange in the system takes place via a carrier such as refrigerant or brine. The compressor / compressor supplies the driving force. When absorbing heat, we speak of cooling, and when giving off heat, we speak of heating

The air conditioning system consists of several components, which are explained here:

Link:  Main components of the refrigeration system

If air is cooled down, moisture can fall below the dew point of the air. Dew or condensation forms and the air is dehumidified. The resulting condensation water or condensate must be drained away.

You can find more information on this under the article Condensation water pipe.

Link: Tauwasserleitung

Depending on how much dehumidification takes place, we change the humidity in the room with dehumidification. A clear distinction must be made between relative and absolute humidity. In the case of absolute humidity, the absolute proportion of water in g / kg as vapor in the air is an important variable. Meanwhile, the relative humidity is a percentage based on a certain amount of air. If you would like to receive more information on this, take a look here.

Link: follows

The HX diagram from Mollier is an important tool for the representation of the air conditions and their changes. It is just as important for the design of air conditioning systems for the required room situations.

Partial air conditioning systems for private use

Air conditioning systems are roughly divided into two classes. In full air conditioning systems and partial air conditioning systems. Common air conditioning systems from the retail trade for the office or the living room at home are partial air conditioning systems.

The difference lies in the number of changes in the air state that is served. Conventional air conditioning systems, which are also used in private use, seldom serve the function of humidifying the air. As soon as an air conditioning system cannot technically operate all four listed changes in state, it is referred to as partial air conditioning systems.

With air conditioning systems, heating by reversing the cycle

Air conditioning systems offer the possibility not only of cooling, but also of heating. This type of heating is becoming increasingly popular. Technically, the circuit of the refrigeration system is reversed. Heat is absorbed from the environment and given off in the room to be heated. It should be noted here that there are physical limits. From a certain outside temperature, the "heating mode" becomes uneconomical or even impossible. The limit of the lowest outside temperature is mainly determined by the refrigerant charged. How economical an air conditioning system is is described, among other things, by the COP or EER of a system.

The COP = net power / electrical drive power. For example, if the COP is "4", this simply means that with 1 kW of electrical drive power, you get a heating power of 4 kW.

Types of air conditioners

plug-in air conditioning systems

The simplest variant of an air conditioning system are compact, ready-to-use solutions. These mobile air conditioning systems can be installed quickly without having to intervene in the building itself. These systems can cool, dehumidify and ventilate. If you follow the installation instructions supplied, everyone is able to install these air conditioning systems on their own. The device is supplied with power via a standard socket.

We would like to point out possible operating errors, which must be read in the operating instructions:

1. Laying the waste heat hose
2. Laying the condensate hose
3. Correct sealing of the hose lead-through to the outside air
4. Maintain minimum clearances to walls or furnishings
5. Note the limits of use
6. Observe the maintenance intervals for cleaning filters or the like.

The common variant of air conditioning systems in the private sector are monosplit air conditioning systems for air conditioning a room. Multisplit air conditioning systems are used for air conditioning several rooms. Important! The installation must be carried out by a specialist. The installation includes the specialist knowledge about the correct laying of the refrigerant pipes and the condensate pipe. The professional installation of the indoor and outdoor units, the correct installation of the electrical wiring is just as important as the observance of Nevaeus and noise development.

Monosplit air conditioning systems

These partial air conditioning systems are used to air-condition a room. Only one cooling zone is served, which can be cooled, dehumidified or heated. A mono-split system consists of an indoor unit and an outdoor unit. Depending on the manufacturer, there are systems whose pipeline is already pre-installed and connected using a quick-release fastener. The systems are already pre-filled with the appropriate refrigerant. The time and installation effort is the least with this system. If the distance between the indoor and outdoor units is greater, the connection between the units via copper pipes must be individually adapted. Here, too, the systems are pre-filled and the filling quantity is sufficient for the entire system.

Multisplit air conditioning systems

These partial air conditioning systems are used when several rooms in a building are to be air-conditioned. Several indoor units can be operated on one outdoor unit. The installation effort is considerably higher with this variant.