Welcome to the Solar Collector
Brainstorming and Development Page!


 

Home

Hot Air Collector

Hot Water Project 1

Hot Water & Space Heating

Solar Electric

Solar Construction 101

FAQs

Best Collectors

Simply Solar
Sign up Calendar Latest Topics
 
 
 


Reply
  Author   Comment   Page 1 of 2      1   2   Next
jezter6

Registered:
Posts: 15
Reply with quote  #1 
Ok, dumb question time. Has anyone put some sort of small economically reasonable heater in their hydronic collector box?

I'm still thinking of design, and one of my most optimal places with the most south facing is somewhat uphill (ie: i'm on a gentle north facing slope, but high enough where the sun isn't obscured by the ridge line)

Right now I've got a rough idea of a similar size as Scott's Hot Water & Space Heating link at the top of the forum.

Option A (in screenshot as "purple"):

Ground Mount a collector like Scott's, but on the hill. Because the space behind it is a somewhat steep bank leading down to my driveway/yard to me it feels like an even bigger sail, and is also further away from the storage tank/pump and will require probably 10-12' more "head"

Option B (in screenshot as "red"):

I'd like to put a pavilion at the bottom of the steep bank for some shady outdoor grilling space. As the collector would be close to or at vertical, it would make a nice "wall" on end, shading the pavilion's inside and would use the pavilion roof supports nicely.

Option C (in screenshot as "blue"):

This is more of a hybrid roof mount, I'd just extend a reasonable pitch roof and cover a portion of the bank. The bottom of the collector is placed at a more flat spot of the bank where one could sink a pole in some concrete, or it could be moved (in this picture left a little) to be more on a traditional roof. I'm not sure WHY I like it hanging out over the bank, other than some additional shade. Also, given the possible size of the roof, I could have room for a second collector above it (or just build this one as big as I can afford).

Downside is obviously winter angle is quite poor, which runs the possibility of collecting snow and ice if it's not at a steep enough angle. Thus, why I asked the question about a small heating element that would warm the glazing just enough to prevent snow buildup and somewhat "pre-heat" the collector so it's not starting from frozen.

Anyway - boredom is striking me today and I'm doing research and figured I would gather opinions from the board if anyone's around and wants to weigh in.


Capture.jpg 


DIYsolarGuy

Registered:
Posts: 21
Reply with quote  #2 
How much snow do you get in the Winter? This is my first Winter with my solar array and I'm not having the snow stay on my panels more than a day or two after a storm. Unless you have long periods of no sun I can't imagine that is going to be a problem, as the nature of solar panels will generate heat by themselves, without a heating element. I like your C option best.
jezter6

Registered:
Posts: 15
Reply with quote  #3 
I'm in Maryland so not much snow until a big noreaster comes and I get 21 inches.
jezter6

Registered:
Posts: 15
Reply with quote  #4 
And for note. The plan is much like Scott's in a ~24' width x 8' height (or 10-12' depending on option C being the answer).

This is for space heating, DHW, a future hot tub, and in summer - above ground pool heat.

"ground" height is approx 6-8' above water tank level if I did a 4'x8' type box in the basement. Plus whatever height a collector would be off the ground. Option B I'd say would be another 10' head (8' collector + 2' of post to hold it up), and option C would probably be on 10' posts plus the angled height of the collector ...maybe total about 15-18' above ground. 


Rick H Parker

Avatar / Picture

Registered:
Posts: 808
Reply with quote  #5 
Quote:
Originally Posted by jezter6
Ok, dumb question time. Has anyone put some sort of small economically reasonable heater in their hydronic collector box?


For melting snow and ice off?  Just pump the heated stored water through the collector. The heat from the stored water will raise the temperature of the collector and deice it.

You don't need to get the collector hot to slide the snow or ice off. Just enough to raise the surface temperature above 32°F (0°C). That will produce a layer of melt which will act as a lubricant between the collector and the solid state water on top of it. Once you poke some holes in the snow cover the sun can take over and finish the task and start pumping up the temperature of the storage tank.

You could add a deicer circuit or a deicer subroutine to a controller that would over ride the pump control for X amount of time then disengage or disengage when the collector reaches a  temperature of say 50°F.

In short: Turn the pump on to deice the collector.

Is this solution economical enough to meet your criteria?

In the case of hot air collectors, turn the fan on.
Dump a little heat into the collector to gain more then you dump.

__________________
Rick H Parker
Kansas, USA
Electronics Engineering Technologist
jezter6

Registered:
Posts: 15
Reply with quote  #6 
That works. I figured the water coming back would chill the storage tank more than it would be worth.
Rick H Parker

Avatar / Picture

Registered:
Posts: 808
Reply with quote  #7 
Quote:
Originally Posted by jezter6
That works. I figured the water coming back would chill the storage tank more than it would be worth.


Any deicer would be dumping energy.

I think you will get a net energy gain, expectedly if the snow is expected to stay for more then one day.  The deicer would be manually triggered, take a look at the weather forecast and make a educated guess. 

__________________
Rick H Parker
Kansas, USA
Electronics Engineering Technologist
jezter6

Registered:
Posts: 15
Reply with quote  #8 
Quote:
Originally Posted by Rick H Parker


Any deicer would be dumping energy.

 


Absolutely.

At this point, I'm just being pedantic about the math because it's all theoretical until I build the system. And I'm a nerd like that.

If I run tank temp water through the collector enough to de-ice/snow, and that drops my temps down far enough that I can't recover that drop completely - is it more efficient to use a little electric before the sun comes up so to it's de-iced and ready vs how much I lose in the tank that I can't put into my radiant heat?




Rick H Parker

Avatar / Picture

Registered:
Posts: 808
Reply with quote  #9 
I think you missed my point. You don't need to bring the collector up to operating temperature. You just need to bring the top surface of the glazing up above freezing then gravity will do the rest. That take a lot less energy. I think your over guesstimating how much energy it takes to deice the glazing. Keep in mind the glazing has the highest thermal conductivity of any component of the collector.


You only need one more component to a dump some heat from the tank.  With an electric heater, your build cost will be much higher and the added complexity means failure is more likely. For as often as you will need it, is it worth it?

__________________
Rick H Parker
Kansas, USA
Electronics Engineering Technologist
jezter6

Registered:
Posts: 15
Reply with quote  #10 
Quote:
Originally Posted by Rick H Parker
I I think your over guesstimating how much energy it takes to deice the glazing.


I think that hits the nail right on the head. I don't know how much energy it would take running hot water through the collector enough to deice and how that would drop the tank temp. I'm presuming there'd be a big drop, but I guess I'd need to see it in place. You're right, I don't want to get it to operating temp, just enough to slide snow off.

Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.

 

web statistics