Calibration - Air Conditioner Calibration - Part I

We hear a lot about the size of the air conditioner when we make an important purchase choice or install it. What does the meaning of the word mean?

Air conditioners are designed to remove heat or add (if the heat pump is included in a single package). Consequently, the “size” of the alternating current will be defined in terms of heat delete or
the ability to add.

The units we use to calibrate the air conditioner BTU / hour (British thermal units per hour) ton , and W Some countries use one unit more than others to calibrate an air conditioner.

This is great if you can remember the relationship between BTU / hour , ton , and W You can quickly estimate the size of the AC, if your friends use units that are unfamiliar to you;

1 ton is equivalent to 12,000 BTU / hour. And,

12,000 BTU / hour is equivalent to 3.516 W - or 3.516 kW (kilowatt).

Concept and basis for determining the size of the air conditioner

It is based on heat gain and / or losses in a building. Obviously, you will need Delete the amount of heat in your home - if it's hot outside. Similarly, you will need Add to heat loss from your home - if the outside temperature is cold.

In short, gain and heat loss should be equally balanced by heat sink and refill to get the desired comfort in the room we want.

What determines the amount of heat and / or addition we want?

It is determined

temperature difference between outdoor temperature and desirable temperature. By common sense, if you want a cool room, in a very hot climate, you will need to remove a lot of heat. On the other hand, it doesn’t take much to keep a cool room on a mild day

building material and the location of your building. Let's say you have two identical houses. One of them is built of glass, and the other is brick and is well insulated.

Of course, one that was built of glass would require much more heat added or removed than the other — on the same day.

Two identical houses with different orientations relative to the direction of sunrise and fall of the sun will also affect the size of the air conditioner.

surface area of ​​the walls. The greater the surface area, the more heat that can be lost or gained through it. Here, the size of the AC that you need affects

Infiltration plays a role in determining the size of our air conditioner. Door gaps, cracked windows, chimneys are “doorways” for air to enter from outside, into your living space. Only you know how it can get upset, feel a draft or hot air from outside.

activities and other equipment in the building. Cooking? Hot bath? Is it a gymnasium with intense exercise?

the tenants. It takes a lot to cool a town hall full of people, right? Oh yes, we give off heat.

Square feet method?

You may have heard about the square feet method in calibrating an air conditioner. In fact, it is often used by many contractors, which we sometimes use arbitrarily. This method was generalized and simplified by contractors, starting with the calibration of many speakers.

The most common relationship is "1 ton for every 500 square feet of floor space." This method May work for a small-scale contractor with a similar type of house or building,
and similar wall material.

But the relationship will not work if you change the design type of the wall, or if you move to another area with a different climate. Simply put, this air conditioner calibration method will work only for a limited group of buildings in a given area.

However, it is a method reasonably useful for installing windows, small splits or portable air conditioners.

Guide j

Now this is how we should calibrate the air conditioner. Manual J is a database with methodologies, formulas, and guidelines for sizing and alternating current. This guide is designed by ACCA (Air Conditioning Contractors in America) - with regular reviews.

It will provide you with the necessary data to calculate the heat gain and heat loss. For the correct choice of the size of the air conditioner, depending on the temperature, you will find the walls, the orientation of the building, infiltration, shading, the number of passengers, the temperature you want to set, the outdoor temperature.

This is a really extensive guide that is used by certified and experienced air conditioning contractors.

Guide J is just a tool. Important things are the values ​​that fit in it. If we enter exact values, our results will be accurate. Otherwise it will not help.

What is the important information you need to have to determine the size of an air conditioner with Manual J? These,

the required temperature range in your space,

Approximate temperature distribution in your area, to find out how many months you have winter, summer and mild weather conditions,

Surface area of ​​the wall and material. Window surface area

Any tinted window? Any isolated space?

How many people will live in each space?

What events are held on any given day? How much cooking? What is the use of hot water?

The orientation of your building relative to the direction of the sunrise and fall of the sun and,

sources of infiltration

,