DESC:FIELD OF INVENTION

The present invention relates to mixed water-based indirect direct evaporative cooling. More particularly, the present disclosure addresses water-flow indirect heat exchanger cooling, where flowing water in the heat exchanger is responsible for the indirect cooling. With the help of indirect cooling, the performance of an evaporative cooling machine will be increased by 20-40 % in terms of heat index.

BACKGROUND ART

A conventional air cooler operates on the principle of evaporative cooling, where hot air passes over a water-saturated evaporative pad, as illustrated in Fig. 1(a). During this interaction, water evaporates and absorbs latent heat, resulting in cooled air with increased humidity. This process is known as adiabatic cooling, as depicted in Fig. 1(b). The air cooler outputs cold, humid air from an inlet of hot air.

Conventionally, the current cooler, as shown in Fig 1 (a), has two main problem areas: the cooling performance and the high-humidity outlet air.

For example, in Rajasthan or a desert area, where there is a high temperature and low humidity environment condition, the air cooler requires a high cooling rate. Still, the current air cooler cannot provide more cooling due to the limitation of adiabatic cooling up to wet bulb temperature when the system has 100 % efficiency; therefore, the consumers are not satisfied. Also, in the case of Mumbai or Kolkata, where there is a medium temperature and high humidity environment condition, the performance of the air cooler is very low due to high humidity. If environmental air has more humidity, then the air cooler cannot cool down the air, and the air cooler increases the humidity in the closed room. Hence, this causes discomfort to humans due to high humidity.

Traditional industrial indirect and direct cooling technology is based on natural evaporative cooling; no other technology has been used. In this indirect cooling part, the secondary air first interacts directly with water and therefore, the natural evaporation happens in the manner that secondary air cools down. Meanwhile, primary air interacts with secondary air indirectly through an air-to-air heat exchanger and cools down the primary air without increasing the humidity. After that, the primary air directly interacts with water and cools down again due to the evaporative process. In these ways, the performance of the system increases, and the primary air cools down more with the same amount of humidity as per Fig 2 (b).

But there are some drawbacks to traditional industrial indirect and direct cooling technology -
1. Air-to-air indirect cooling takes more space for installation.
2. Air-to-air heat transfer rate is slow due to the low specific heat of the air (1 KJ/Kg)

Due to its heavy construction, this technology is used in industrial applications where space is not constrained, but it cannot be used for residential use, where space is one critical parameter. Hence, this invention is a new system called “Water based Indirect direct evaporative cooling with air mixing.”

The present invention caters to address the above problems.

SUMMARY OF INVENTION

The herein disclosed an innovative system design that improves cooler performance without using refrigeration or TEC technology. The herein disclosed system is called Water based Indirect direct evaporative cooling with air mixing. In this system, inventors use water for indirect heat exchanger cooling, which reduces inlet dry and wet bulb air temperature without increasing the humidity. Additionally, we mix secondary and primary air to fully utilize the airflow, resulting in a decreased air temperature. When this mixed air interacts with direct evaporative cooling, the outlet temperature of the air is less with the same amount of humidity than a traditional cooler.

Therefore, such as herein described, there is provided a water based indirect direct evaporative cooler with air mixing comprising of a secondary airflow module facilitating the secondary air to directly interact with water, resulting in evaporative cooling and lowering the temperature of the secondary air; an air – to – air heat exchanger configured to interact indirectly with the primary airflow with said cooled secondary air thereby cooling the primary air without increasing its humidity; a primary airflow module facilitating the primary air directly to interact with water again and further cooling down due to the natural evaporative adiabatic cooling; and a fan configured for forced delivery for said cooled primary air.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Fig 1(a) illustrates a traditional cooler with natural evaporative technology as a prior art;

Fig 1(b) illustrates a traditional cooler with natural evaporative technology in the psychrometric chart as a prior art;

Fig 2(a) illustrates another traditional industrial cooler with indirect direct evaporative cooling technology as a prior art;

Fig 2(b) illustrates another traditional cooler with indirect, direct evaporative cooling technology in the psychrometric chart as a prior art;

Fig 3 (a) illustrates Water based Indirect direct evaporative cooling with air mixing working diagram in accordance with the present invention;

Fig 3 (b) illustrates Water based Indirect Direct Evaporative cooling with air mixing psychrometric chart in accordance with the present invention;

Fig 4(a) illustrates the) water cooling unit working principle of Water based Indirect Direct Evaporative cooling with air mixing in accordance with the present invention;

Fig 4(b) illustrates the airflow diagram of Water based Indirect Direct Evaporative cooling with air mixing in accordance with the present invention;

Fig 5 (a) illustrates the Water based Indirect Direct Evaporative cooling with air mixing in accordance with the present invention;

Fig 5 (b) illustrates the isometric view of the Water based Indirect Direct Evaporative cooling with air mixing in accordance with the present invention;

DETAILED DESCRIPTION

In Fig. 1(a), a conventional evaporative air cooler is depicted, where air directly interacts with water and cools down due to the adiabatic evaporation cooling process. This adiabatic cooling process is illustrated using a psychrometric chart in Fig. 1(b).

Fig. 2(a) shows an industrial indirect-direct evaporative cooling (IDEC) system commonly used in factories. This system features two types of airflow. The secondary airflow directly interacts with water, resulting in evaporative cooling and lowering the temperature of the secondary air. This cooled secondary air then interacts indirectly with the primary airflow through an air-to-air plate heat exchanger, cooling the primary air without increasing its humidity. This process is represented as a straight line in the psychrometric chart shown in Fig. 2(b) (IDEC process line). Subsequently, the primary air directly interacts with water again, further cooling down due to the natural evaporative adiabatic cooling process. The limitations of this industrial system and its unsuitability for residential use have been discussed in the background art section.

This invention relates to the Water based Indirect Direct Evaporative cooling with air mixing, as shown in Fig 3 (a), where the flow diagram of this cycle, particularly flowing water in the heat exchanger, is responsible for the indirect cooling. But the outlet water of the heat exchanger gets heated, and the water temperature increases. Here, for the water cooling, the secondary direct evaporative system is responsible for where the direct evaporation process cools down water, and the water temperature tries to reach the secondary air web bulb temperature.

The primary air, when mixed with secondary cool air, the dry and wet bulb temperature of mixed air is reduced as shown in Fig 3 (b) as a 0-1 process of a new cycle. After that, the mixed air interacts with the heat exchanger, where indirect cooling happens, as shown in Fig 3 (b) as a 1-2 process of a new cycle. In the indirect cooling process, only the air is cooled down, but the humidity of the air is constant. After that, the mixed air interacts with a wetted honeycomb pad, resulting in direct evaporation. Due to direct evaporation, the temperature of the air is reduced with an increment in humidity level, as shown in Fig 3 (b) as a 2-3 process of a new cycle. Water based Indirect Direct Evaporative cooling with an air mixing system can improve the air cooler’s cooling performance and reduce the outlet air humidity level.

Secondary airflow: Here, secondary air flow interacts directly with water cooling unit water and cools down both secondary air- and water-cooling unit water due to the evaporation cooling process. Then, this outlet of the water-cooling unit (secondary air flow) mixes with the primary airflow.

Water based heat exchanger: - Cooled water from the water-cooling unit flows through the heat exchanger. Mixed airflow interacts with the heat exchanger and cools down without a change in humidity. In this process, the outlet of heat exchanger water heats up. After water comes to the water-cooling unit, it cools down due to the evaporation process (explained in point 1 above)

Primary airflow: First, Primary airflow is drawn by the cooler's main fan. This primary airflow is mixed with secondary airflow and becomes a mixed airflow. After mixed airflow interacts with the water-base heat exchanger, it cools down without changing humidity. Finally, mixed air interacts with the main cooler evaporative pad and cools down with increased humidity due to the adiabatic evaporative process.

Water cooling unit (housing): The water-cooling unit is a small evaporative cooling system in which secondary air interacts with water directly, causing adiabatic evaporative cooling. Therefore, the secondary air and water of the water-cooling unit are both cooled down. Parts like a secondary fan, evaporative pad, and water pump are used for the evaporative cooling process.

Water based Indirect Direct Evaporative cooling with air mixing:
In this invention, the secondary cold air is mixed with primary hot air; after that the mixed airflow interacts with a water-based heat exchanger for further cooling. This heat exchanger water is cooled down in the water-cooling unit. In the traditional method, an air-to-air indirect heat exchanger is used, and it requires more space. In the present invention, water is the medium of indirect heat exchanger cooling; therefore, the size of the indirect cooling unit is smaller than that of an air-to-air indirect heat exchanger.

Here, there are two systems:
1. Water cooling system and
2. Air-cooling flow path

1. Water cooling system: Water is responsible for primary air cooling in the indirect heat exchanger unit. But after cooling the air, the water gets heated, and the outlet water temperature of the heat exchanger is high. For continued indirect cooling, a water cooling system is required, which cools down the temperature of the water. Here, we used an evaporative cooling system, which reduces the water temperature, as shown in Fig 4(b).

2. Air-cooling flow path: The primary air is mixed with secondary cool air, which is the outlet of the water-cooling chamber. Due to this mixed air, air temperature is reduced, and humidity is increased. The mixed air then interacts with an indirect heat exchanger, where it cools down without adding humidity. When mixed air directly comes in contact with a wetted pad, it results in direct evaporation, and hence, the mixed air temperature cools down with increased humidity.

In Fig. 4(a), the newly invented system is illustrated, where an innovative component is integrated with a traditional air cooler system. The conventional cooler, labelled as A (natural evaporative system), includes components such as a primary fan, evaporative pad, and water pump. The new innovative system, attached to the traditional air cooler, is designed to cool secondary air and facilitate heat exchange for indirect water cooling. This new system is divided into three zones: indirect cooling, mixing zone, and water-cooling unit. Key components include a water-cooling unit and a heat exchanger. Fig. 4(b) details the water-cooling unit, showing components like an evaporative pad, a secondary fan, and a pump for water flow in the heat exchanger.

In Fig. 5(a), the complete system is shown, featuring the traditional air cooler integrated with the new innovative components such as a heat exchanger, fan, evaporative pad, and pump. An isometric view of the invention system is provided in Fig. 5(b).

As shown below in Table 1, we have tested traditional air coolers and our present invention concept in two conditions: first one high temperature and low humidity (like 45 C and 25 % RH, Delhi or Rajasthan area condition) and second one medium temperature and high humidity (like 35C and 60% RH, Mumbai area condition). Our invention cooler has a higher cooling rate than conventional air coolers.

Table 1: Comparison of cooling performance of traditional air cooler and our Present invention

High temperature and low humidity Medium temperature and high humidity
Inlet Temperature Outlet Temperature Inlet Temperature Outlet Temperature
Traditional cooler 45 36 35 32.3
Invention Cooler 45 34 35 31.6
% Improvement 22.2 25.9

Many modifications may readily be contemplated by those skilled in the art to which the invention relates. Many further modifications may readily be contemplated. The description set out above is particularly applicable to high-rate clarification applications. However, in conventional clarification where the different traditional processes herein described are not used, the teachings according to the invention may have considerable merit and are also applicable. The specific embodiments described, therefore, should be taken as illustrative of the invention only and not as limiting its scope as defined herein.

,CLAIMS:
1. A water based indirect direct evaporative cooler with air mixing comprising of:
a secondary airflow module facilitating the secondary air to directly interact with water, resulting in evaporative cooling and lowering the temperature of the secondary air and water from the water-cooling unit;
a mix air flow module where Cold secondary air is first mixed with primary air, which become cools down due to mixing;
an air-to-water heat exchanger configured to interact indirectly with the mixed airflow so it cools down without increasing its humidity;
a primary mixed airflow module facilitating the mixed air directly to interact with water again and further cooling down due to the natural evaporative adiabatic cooling; and
a fan is configured for forced delivery for said cooled mixed air.

2. The water-based indirect, direct evaporative cooler, as claimed in claim 1, wherein said cooler is divided into three zones namely: a mixing zone, an indirect cooling zone, and a natural evaporative zone.

3. The water-based indirect, direct evaporative cooler, as claimed in claim 1, wherein said secondary airflow module includes an evaporative pad, a secondary fan, and a pump for water flow in the heat exchanger.

4. The water based indirect, direct evaporative cooler, as claimed in claim 1, wherein said primary air is mixed with secondary cool air at the outlet of the water-cooling chamber and due to this mixed air, air temperature is reduced, and the humidity is increased.

5. The water-based indirect, direct evaporative cooler, as claimed in claim 1, wherein said mixed air directly comes in contact with a wetted pad results in direct evaporation, and the mixed air temperature cools down with controlled increased humidity.

6. A process for delivering cool air employing water based indirect direct evaporative cooler with air mixing comprising steps of:
providing a secondary airflow module facilitating the secondary air to directly interact with water, resulting in evaporative cooling and lowering the temperature of the secondary air;
providing an air-to-water heat exchanger configured to interact indirectly with the primary airflow with said cooled secondary air, thereby cooling the primary air without increasing its humidity;
providing a primary airflow module facilitating the mixed air directly to interact with water again and further cooling down due to the natural evaporative adiabatic cooling and
delivering cooled mixed air through a fan.

7. The process for delivering cool air, as claimed in claim 1, wherein said cooler is divided into three zones: namely mixing zone, indirect cooling zone, and natural evaporative zone.

8. The process for delivering cool air, as claimed in claim 1, wherein said secondary airflow module includes an evaporative pad, a secondary fan, and a pump for water flow in the heat exchanger.

9. The process for delivering cool air, as claimed in claim 1, wherein said primary air is mixed with secondary cool air at the outlet of the water-cooling chamber, and due to this mixed air, air temperature is reduced, and humidity is increased.

10. The process for delivering cool air, as claimed in claim 1, wherein said mixed air directly comes in contact with a wetted pad, results in direct evaporation, and the mixed air temperature cools down with controlled, increased humidity.