Discussion on light & heat efficiency

[JayTheDragonTamer]

Hey again. Things have been great with Spike and his custom viv. He’s doing well.

All has been fine up until a visit from my Dad (who has a degree in mechanical engineering). I’ve mentioned this before, but we live in the outskirts of the UK where the cost of living is high, and this mean materials, electricity and other resources are not cheap.
So efficiency is very important, and not something I’d really thought about until now.

After seeing my enclosure with its multiple bulbs and asking about heating and wattages, my dad was not impressed. My setup and its proposed finished design (the lid of the tank is a WIP) is apparently not at all cost effective or energy efficient. And although I value functionality far above efficiency, and I definitely prefer using tested and widely used practices, I have to say… I see his point.

I’ll go ahead and say it- my father is a very stubborn man. He knows more than me when it comes to engineering and physics for sure, but he knows next to nothing about reptile keeping. And he has starting coming up with specifications suggestions to help me stop wasting energy, which are.. interesting I guess. Some of them can be ruled out immediately, but some of them I am actually curious about. I’m willing to tweak my methods a bit to compromise with him, and I was hoping for suggestions and advice from the community as well.

This thread is to discuss efficiency and things that can be changed to decrease the loss of heat, uvb, and light in an enclosure while keeping proper husbandry.

 

[CooperDragon]

It's certainly worth spitballing ideas about efficiency if it can help out in the long run. We're always learning new things and improving upon what we have. What types of changes did he suggest? Using materials that have higher insulation values can be beneficial for efficiency, but in practice they don't always work out as well as on paper. It's still important to have sufficient airflow/ventilation and to have the enclosure cool down overnight. It's important to provide sufficent UVB exposure and to provide a wide enough area of high temps to allow for even basking. Creating a gradient that allows for basking temps in one area and cool temps in another is also important. Using energy efficient materials may wind up requiring a lot more space to achieve these gradients than expected.

 

[JayTheDragonTamer]

So first off, some details. My enclosure has a glass front and sides, and a wooden frame and back. The current lid is a temporary mesh top, while I work on the final piece. Because I’ve just built this enclosure, Im not thinking about redesigning whole elements yet. [But in the future I think I’d have more wood and less glass because wood insulates well- a glass face and glass doors, but the rest of the enclosure would be wood.]

A couple things:
1) I am having to use high wattage, reptile-specific heating bulbs since the UK banned the sale of halogen/iridescence/fluorescent bulbs to consumers outside of the specialty areas they must be used. This means no GE or Phillips halogen floodlights or general household bulbs that produce heat- I can only find LEDs. Limited options has me trying to heat a large enclosure with 150w Daylight basking bulbs and 100w Solar basking bulbs. I am running 2 or more heat bulbs like this, as well as a CHE, all day at the moment and only just achieving good basking temps.

I know out of halogens and iridescent bulbs, halogens are typically hotter and more energy efficient, so these would be my go-to. I should be able to get most Arcadia products.
Does anyone which reptile specific heat bulb puts out PLENTY of heat but doesn’t have excessive wattage? Alternatively, does anyone know where I could source heat producing bulbs not specific to reptiles?

2) My enclosure has circular vents along the back near the bottom, and a mesh top (currently). All of my vivs have had mesh tops up until now, but concerns around heat loss are making me reconsider whether I’d be better off changing that design- I still want my heat source mounted on top of the enclosure. 20in height does not provide adequate room to safely have it inside imo.
I’d like to know what you guys think about closed top enclosures vs mesh, and how these things affect humidity, ventilation, and heating. After a lecture on air intake needing to be proportional to loss of air from the mesh, hot air rising, and that sort of thing, I’m considering ventilation like this: https://www.beardeddragon.org/media/f60267c8-4ad5-4b9f-bf61-575e0d45db7e-jpeg.64784/full

I would have a half mesh, half wood lid- allowing airflow from the vents in the back, up to the mesh along the top at the front. I may include a small square of mesh within the wood portion of the lid, to set my heat source on. The uvb will of course be mounted on the inside of the enclosure, screwed into the wood at the top back, and positioned to overlap with the basking spot.

Does this sound like a good design? Any considerations or alterations?
The goal of a more closed off enclosure is to prevent the loss of heat from the top and create a constant heat gradient. My concerns are primarily about stagnant air and overheating, as well as managing humidity.

3) All my lighting and heating has reflectors. My dad does not believe this is enough and suggested fitting a metal sheet to the inside top of the enclosure and screwing fixtures into it. Obviously- this is a massive massive hazard for overheating. I cannot stress how much I do not want to turn my enclosure into an oven lol. Dangerous in a whole number of ways. I will NOT be doing that.

Having said that, I am curious what you guys think in terms of a more “reflective” top. Not by adding any metal- but by painting the inside of the lid white. (Silver??) Would this have any significant impact? IF the white paint reflected any amount of light, would this be beneficial or harmful? The question is, whether a reflective top would help utilize a light source or whether it would cause glare. Then there’s the question of the reflected rays. Could this be harmful to the reptile’s vision? I am curious about this idea in theory.

Reply if you have any additional comments or ideas too.

 

[JayTheDragonTamer]

It's certainly worth spitballing ideas about efficiency if it can help out in the long run. We're always learning new things and improving upon what we have. What types of changes did he suggest? Using materials that have higher insulation values can be beneficial for efficiency, but in practice they don't always work out as well as on paper. It's still important to have sufficient airflow/ventilation and to have the enclosure cool down overnight. It's important to provide sufficent UVB exposure and to provide a wide enough area of high temps to allow for even basking. Creating a gradient that allows for basking temps in one area and cool temps in another is also important. Using energy efficient materials may wind up requiring a lot more space to achieve these gradients than expected.

I went into detail in a reply to my thread and didn’t notice your comment until I refreshed the page. Thanks for responding so fast.

I definitely agree. I won’t be doing anything that risks damaging my husbandry. I absolutely want to keep everything to the highest standard- but I’m interested in seeing if I can find more efficient ways to get it there. I believe I have some areas I need to improve on.

For example, I know what temperature I need my basking spot to be, and the correct temperature gradients, but how I’m getting those results at the moment isn’t ideal. I’m currently having to use multiple, high wattage bulbs. Running 150ws and 100ws and other bulbs all day to keep the right basking temps. It’s a huge mess of wires and domes, and the amount of energy I’m using is not producing the amount of heat it’s worth.
But I know from lots of anecdotal evidence that for my size enclosure, I should be able to reach the correct basking temps with much less wattage. I also know from past experience that the right type of 90w halogen floodlight is capable of creating really decent heat and light. For whatever reason, I’m missing the mark with my heating, and I could be doing so much better. My plan for efficiency is finding out where the energy loss is and targeting that, to achieve the same results, but in a better way.

 

[CooperDragon]

Based on what you said in your previous post, it sounds like you have limited options for lighting, unfortunately. I know Komodo and Arcadia make basking lights that are very similar to the hardware store brands, so that may be the way to go. I'd check Swell Reptiles and see what they have on hand and maybe try out a few options and see what works best. I think in most cases you should be able to reach basking temps with a single wide/flood bulb.

I think there is a balance between efficiency and practicality. Your vent design should work, but it might be better to have the vents low on the cool side (Rather than the front) and high on the warm side (and/or the back) to make the best use of convection. In my enclosure, I leave the top off completely to allow for overhead space for the lighting. I just have it hanging over the top on adjustable stands. I'm in the opposite spectrum in that I don't care much about efficiency (energy is very cheap here). What you might try is to build the frame so that you can slide a solid top in from the side along a rail system like what a drawer uses. That way you can adjust the size of the open end for the lighting and take it out if you want to. I'd go for adjustability over permanent configurations.

Most of the heat bulbs have parabolic or bulge reflectors built into them, so you don't necessarily need a dome fixture. I think lining the top with reflective metal may be going too far in the opposite direction. I suppose something like that could be added later on if you aren't able to achieve the proper temps, but I've never seen a case in which that was needed. I think that if you can keep the ambient room temps fairly warm and use some kind of top to control heat loss upward, then that should do well enough and further effort would lead to diminishing returns in most cases.