Subject: | |
From: | |
Reply To: | |
Date: | Mon, 4 Jan 2021 16:36:05 -0500 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
I was finally able to take some videos and some images of my cluster with my IR camera. This was just a quick 15 min test. I did try a couple of days before but had some issues with my setup (no elastics holding camera to stick). I will make another small modification. After the exercise, once the sensor data and then a bit of looking through the IR images/video, I had a aha moment, as to why my hive "disturbances" seemed to have on-going effects (extended high temperatures for 2 to 3 days). My hypothesis is, this is the effect of the thermal mass of honey/bees/wax/wood absorbing the excess heat during the 10 hours of increased meta rate (peak of about 50W/hr back down to the average of 9-11 W/hr for a gain of about 176Whrs). The heat loss is about 3-4 Watts/hr so it would take about 40 to 50hrs to release the extra heat and go back to the cluster's desired equilibrium. The attached pdf link is technical but I am attempting to show some possible applications of thermal imaging. Most people just take outside photos of their hives but don't know how or know about the free software Flir makes available. (not a recommendation for going out and buying a camera)
I did include a few slides on how I determined thermal energy gain (based on before and after (2-hour interval) temperature profiles).
So the point of the story is that in insulated hives (especially with no top entrance), the heat gain is significant, the heat loss is low so it takes much time to dissipate the heat gained by the disturbance event. In a wooden hive this wood just seem like a quick temperature spike as the heat loss is much higher the hive setup likely include lots of top ventilation.
I was also having a thought about the heater bees heating from below and how it was very intuitive from a natural ventilation perspective, heating efficiency (heat rising causing thermal transfer to superorganism content: honey, bees, wax, wood, etc..., cool incoming air is preheated by the exiting warm air,). I am not ready yet to rock the boat 🙂. This would be yet another difference between colonies wintering in a well-insulated in small cavities (single brood box). The temperature profile in my double is very different than this single brood hive. I am finally understanding what Derek Mitchell meant by the MCR (colony mass to lumped enclosure thermal conductance) in real terms and what good may look like.
Here is a link to the video - https://youtu.be/TRKnxxaTNwo
Associated Slide Show: https://drive.google.com/file/d/1RKV08ZX0KA-KtRCzdI-qVzUPOdc6oC0b/view?usp=sharing
It's -30 this morning so hopefully in the next few days (warmer) I can get back in the hive and take new pictures and video in a more organized way. I am modifying my setup a bit more to reduce the height that should allow me to slide it in with even less disturbance. I need to get IR pictures without getting that initial heat spike as that is them responding to me vs a steady state cluster.
Best wishes for the new year!! I was very saddened by Aaron’s departure.
***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
|
|
|