My house was built in 1957 and they basically slapped baseboard along every outside wall of every room, plus some more where it was convenient, for a total of 178' of baseboard in an 1800 sq ft house. A pessimistic heat loss estimate/calculation for the house comes in at ~75,000 btu/hr at an outdoor design temp of 10 (although given tonight's temp maybe that should be 0). Historical oil consumption roughly supports this estimate.
I am working out a design for my EKO 40 install and am trying to figure out about a zillion different things, one of which is how much heat I need to deliver to keep the house warm at a given outdoor temp. Here are a few tables I put together to try and figure out this relationship. The first is baseboard output at different temps from the Slant Fin documentation. The second is the house load at various outdoor temps, how much baseboard output needed to satisfy the load, and finally how
![Circulator Run Time / Outdoor Reset Circulator Run Time / Outdoor Reset](https://www.hearth.com/talk/data/attachments/122/122702-3dda3d3873c51cbd3e66578dec126fb0.jpg)
If we assume 480/btu/ft baseboard output at 170 avg temp (180 in 160 out), that makes 85,000 btu/hr, or 10,000 btu/hr over what's needed at 10 degrees out, and 47,000 btu/hr more than what's needed at 40 degrees out. At 170 avg temp I am figuring the load circulators would run 75/85 or 88% of the time at 10, and 44% at 40.
Does this all look correct? What is benefit/drawback to circulating cooler water more frequently vs hotter water less frequently to meet demand? Extending the usefulness of storage at the expense of electricity saved in pumping? A more stable house temp?
This relationship of lower water temp vs outdoor temp is why an outdoor reset exists, correct? My limited understanding of modcon boilers is they like to make lower temp water and therefore benefit from running lower supply temps... how is an ODR useful in a wood boiler setup?
I am working out a design for my EKO 40 install and am trying to figure out about a zillion different things, one of which is how much heat I need to deliver to keep the house warm at a given outdoor temp. Here are a few tables I put together to try and figure out this relationship. The first is baseboard output at different temps from the Slant Fin documentation. The second is the house load at various outdoor temps, how much baseboard output needed to satisfy the load, and finally how
![Circulator Run Time / Outdoor Reset Circulator Run Time / Outdoor Reset](https://www.hearth.com/talk/data/attachments/122/122702-3dda3d3873c51cbd3e66578dec126fb0.jpg)
![Circulator Run Time / Outdoor Reset Circulator Run Time / Outdoor Reset](https://www.hearth.com/talk/data/attachments/122/122701-2e9dbb2f571a3386597fc468dfa1573e.jpg)
If we assume 480/btu/ft baseboard output at 170 avg temp (180 in 160 out), that makes 85,000 btu/hr, or 10,000 btu/hr over what's needed at 10 degrees out, and 47,000 btu/hr more than what's needed at 40 degrees out. At 170 avg temp I am figuring the load circulators would run 75/85 or 88% of the time at 10, and 44% at 40.
Does this all look correct? What is benefit/drawback to circulating cooler water more frequently vs hotter water less frequently to meet demand? Extending the usefulness of storage at the expense of electricity saved in pumping? A more stable house temp?
This relationship of lower water temp vs outdoor temp is why an outdoor reset exists, correct? My limited understanding of modcon boilers is they like to make lower temp water and therefore benefit from running lower supply temps... how is an ODR useful in a wood boiler setup?