Sizing and Selection of ETS equipment for your needs
Determining the model(s) or size(s) of ETS equipment needed for your application is just slightly different from sizing up conventional heating units. It is important to accurately determine the size (and quantity) of units needed to satisfy your heating needs. Improper sizing (over or under) may have an adverse effect on system and installation cost as well as efficiency and comfort. Your local dealer will assist you with this process. There are three basic steps in determining appropriate heater size:
Step 1: Calculate the heating requirement (heat loss rate) for the area you intend to heat.
Step 2: Determine the number of off-peak hours available (based on electric rate from your power supplier or your facilities load profile).
Step 3: Select the model (unit) that will satisfy the heating requirement based on off-peak hours available.
Step 1: Calculate the Heating Requirement
Several factors impact the heat loss rate (or heating requirement) for an application. These include:
- Size of area to be heated
- Quality of construction - i.e., insulation value of walls, ceilings, windows, doors, etc., (usually referred to as R-Value or U-Value)
- Infiltration rate and/or fresh air requirements
- Indoor room temperature desired to be maintained
- Your local winter weather conditions
There are various energy auditing software programs which dealers use to guide them through the process of determining the heat loss rate. To most accurately size heating equipment and ensure total comfort even on coldest days of the year, a complete heat loss calculation must be completed. For a rough estimate, short cut methods many times are used.
Step 2: Determining the Number of Off-Peak Hours Available
Contact your local power company to find out how many off-peak hours are available per day and what the times are. If you are a C&I account, your Facility Manager will review the power load profile of your building to determine the number of off-peak hours available during the typical day and what those times are.
Step 3: Selecting the Heater Model that will Satisfy the Heating Requirement Based on the Off-Peak Hours Available
Once the heating requirement has been determined and you know the number and duration of off-peak hours available to you, you can now determine the size of ETS equipment needed to satisfy your needs. Below you will find a table which indicates the amount of heat loss each heater model can satisfy under a sampling of utility off-peak hour strategies. Simply select the heater model that will satisfy your heating requirements based on the corresponding off-peak hours.
For commercial and industrial (C&I) applications, please also refer to the heat delivery graphs in the technical data sheet for the specific products. You can find these in the Downloads section of this web site.
Click here for a larger version of the following chart.
| Off-Peak Hrs per day |
| Model |
8 Hrs Continuous
(BTU/HR) |
12 Hrs Continuous
(BTU/HR) |
18 Hrs Continuous
(BTU/HR) |
8 Night + 4 Day
(BTU/HR) |
|
Room Units
|
| 2102 |
3,700 |
4,900 |
9,825 |
7,540 |
| 2103 |
5,525 |
7,350 |
14,775 |
11,325 |
| 2104 |
7,150 |
9,825 |
19,700 |
15,100 |
| 2105 |
9,200 |
12,317 |
21,100 |
18,900 |
| 2106 |
11,100 |
14,775 |
22,150 |
22,150 |
|
|
|
|
|
|
Whole House Systems
|
| 3120 |
23,500 |
31,350 |
62,700 |
47,100 |
| 4120/5120 |
34,000 |
45,550 |
81,400 |
54,200 |
| 4130/5130 |
49,200 |
65,600 |
122,000 |
81,300 |
| 4140/5140 |
65,600 |
87,500 |
131,000 |
99,700 |