Last Updated on July 3, 2022
Swamp cooler is a simple appliance for cooling indoors and outdoors. Air passes through high surface area cooler pads soaked with water. This causes evaporation and as a result we get cool air. What if this surface area is increased by increasing thickness of pads? Will it increase cooling of your swamp cooler? Can you double up your swamp cooler pads?
Swamp cooler pads can be doubled up to increase cooling effectiveness as this increases surface area and water retention. However, if hindrance caused by cooling pads is significantly high compared to airflow by blower, this could actually lower cooling. Blower motor power, pump size and number of distribution lines are factors that determine effectiveness of using multiple cooler pads.
In general, there are 2 main variables that decide whether cooling will increase or decrease by doubling up your cooling pads. One is air flow rate and other is water retention by your cooler pads.
If cooler pads are thickened to maximize water retention, but hindrance to air becomes very high considering power of blower, then this will actually decrease cooling instead of enhancing it.
In the same way, when airflow by blower is maximized at the expense of thinning of cooler pads, then evaporation is compromised. We know when it comes to swamp cooler, with less evaporation there is less cooling.
So, will it work for you? How to do it right? No worries, I have written this article to share with you what I have learned and exactly what you need to know?
Role of Cooling Pads in Swamp Cooler
Swamp cooler performs cooling by evaporation of water. When water evaporates it converts from liquid state to vapor state. This requires heat energy. This is the same heat that is extracted from air. So, what we receive from the front end of cooler is cool humid air.
Well evaporation is for sure required, but where do cooling pads fit in?
Actually, the water has to be contacted with air in order to evaporate and take heat from it. The more the air comes in contact with water the greater is evaporation and thereby higher is cooling.
This is where cooling pads come into play. They have very high surface area and ability to retain water for a long time. Water is consistently delivered in a well spread way by water distributor. Air rushes through pads that are soaked in water and evaporation occurs. The contact area is already maximized by pads to maximize this evaporation.
Why Doubling Up Cooler Pads Can Increase Cooling?
As I discussed earlier, maximizing contact between water and air is the key to higher evaporation and ultimately greater cooling.
When cooling pads are thickened by stacking against each other surface area increases. This means that air can now contact more water per second that it did earlier. The result is increased evaporation. This is the reason why you get better cooling with thicker cooling pads.
Further, even if the water delivered per second remains same, doubling up cooler pads increases water retention quantity and time. More water staying for longer time in your cooler pads means more water evaporated and more heat taken from air.
When will Stacking Cooler Pads Work for You?
Surely increasing thickness of cooling pads would increase surface area and ability to retain water, in more quantity and for more time, to improve evaporation.
Relation of Airflow with Cooling of Swamp Cooler
However, there are other variables that have to be taken into account, to know that doubling up your cooler pads will actually work. If they are neglected, not only this technique may not be effective but it may actually reduce cooling.
The most dominant factor in deciding, whether using two cooler pads with each other will be effective or not, is the airflow.
The blower in your swamp cooler is operated by a blower motor. The motor is restricted by its power rating (horsepower). Motor rotates to rotate blower, that delivers air through the cooling pads. The maximum airflow that can be attained during this situation is when there are no cooling pads. But in this case, there will be no actual cooling by evaporation.
Side Effect of Thickening Cooling Pads
With the increase in thickness of cooling pads, the restriction to air also increases.
Let’s say you have a swamp cooler, in which total air has to go through 3 cooling pads for evaporation, before it is delivered from the front. Stacking up each with another cooling pad would make a total of 6 cooling pads.
Or in other words, each cooling pad is doubled in its thickness. Roughly the hindrance will also be doubled. Thereby, two times will be the effort required by blower roughly, to maintain the same flow rate, as with single cooling pad on each side.
If the airflow rate significantly drops due to limitations of motor, then stacking up will not effective. Despite more contact and quantity of water available at cooler pads, there will not be enough air to cause enough evaporation.
There is a balance that has to be maintained between thickness of cooler pads and the ability of the motor to withstand the restriction offered by increased thickness of cooling pads.
Note: There is a wide range thereby, where your cooler will perform better with dual cooling pads, but if the restriction exceeds from certain threshold, then you will see a drop in cooling instead of increment.
Blower Motor Limitations
Another indicator that tells you that your swamp cooler motor is not compatible with using multiple cooler pads, is overheating of the motor.
If you turn your motor to high and after sometime it shifts to low speed, this means that motor is heating up and thermal protection is preventing motor to operate at higher speed.
This doesn’t necessarily mean that your swamp cooler is not compatible with using doubled up pads. There are several reasons why this could happen. But if it happens quite often after installing multiple cooler pads, this might be an indication that your motor is not bearing this restriction of airflow.
How To Maximize Cooling with Modified Cooler Pads?
After cooler pads have been thickened, by combining them with each other, surface area and ability to hold water has been increased. However, in order to take full advantage of modified cooler pads, there are certain measures and replacements that you need to perform.
They are not necessary but rather recommended if you want maximum cooling by your swamp cooler.
Higher Power Blower Motor
A major factor that limits airflow from blower is power of the motor driving it.
Even if air is not significantly restricted by using multiple cooling pads and overall cooling is increased, still you could use a higher power motor to increase airflow.
Higher airflow will result in higher evaporation. The reason is more air coming in contact with soaked doubled up cooler pads. Ultimately, high power motor will directly impact cooling.
As capability of pads to retain water is increased roughly twice, evaporation can also be increased to almost twice, and so does cooling.
You can use larger pump, that delivers more water through the cooler pads, that have higher water retention ability now. The water flowing per second through the cooler pads will be increased. As a result, you will get higher evaporation.
Increasing Distribution Lines
If cooling pad is partially dry during running of your swamp cooler, then dry part will not contribute in evaporation. This will cause immense drop in the cooling ability of your swamp cooler.
Every season check distribution lines and holes for clogging. For cleaning distribution lines internally, use spider cleaner. I picked one for you. Well actually 2 in 1 packaging. Click here to see specifications.
More distribution tubes mean better spread of water. They will help soak your cooler pads better, especially when thickness is doubled after combining two with each other.
I choose a complete distributor kit for you. It’s cheap and usually you will not run into issues while fitting. However, it is a good idea to give a look at the dimensions. You can check specification of the product by clicking here.
Note: You do not need to change everything, given in this section, that can be improved. If cooling is increased by doubling up cooler pads, then that’s great, you don’t need to do anything. But if you want to maximize the performance of your swamp cooler, it will require some replacements, especially the limiting component.
Most Effective Cooler Pads (In My Opinion)
When it comes to cooler pads, there is a lot of variety. I have looked into many pads, every type has some pros and cons. So you have to compromise between merits and demerits.
Based on performance though, I rate aspen swamp cooler pads the coolest. They will usually give you the highest temperature drop. Besides that, woody odor is great to smell.
However, one annoying thing about them is that have less life. They have to be changed at least once in every running season, as they flake off quickly with time. These fragments can clog pump and distribution tubes, partially if not entirely.
Solution: Drain your swamp cooler now and then using drain valve to get rid of the flakes. I personally recommend using a combo of purge pump and filter screen. Filter screen will prevent debris and flakes from clogging your pump and distribution tubes. While purge pump will prevent scale and mineral buildup by draining water automatically every few hours. This specific one that I selected for you does it after every 8 hours.