Hive internal temperature monitoring

[john t]

This may be of interest, as for the practical use im not sure but welcome comments.
I have been monitoring the internal hive temperature /humidity using a small data logger, I have placed the device in the hive inside a sock, it was placed on the top bars which are covered with insulating material, the device logs the temperature and humidity and dew point at intervals which I have set to record every hour.

The device is called a TEMPO DISC™ Bluetooth wireless thermometer purchased from amazon £40 It is the size of a 50 p coin, and connects to your phone via Bluetooth, so I can download the data without disturbing the hive, the temp/humidity /dew point readings can then be emailed from the phone as a doc and used in a spreadsheet, it also produces graphs and can send alerts so all in all quite a powerful bit of kit,

I placed the tempo disc in the hive at the end of February before I went away on my holls, and downloaded the data the other day on my return, the temp that I recorded ranged from 12 c to 22c unfortunately as I was away I wasn’t able to record the outside temps but it was well below freezing for quite a few days and snowed in Hampshire

Example of data downloaded :- Time 12:00 24/02/2018
Temp =14.1c
Humidity = 75%
Dew point = 9.9c

One observation I have noted is that the hive temperature is always about 6 to 8 deg c above the dew point, I will take some external temperature readings together with internal readings to compare and post at another time, I intend to leave the device in the hive throughout the coming season and will try to add more info if anyone is interested and post some pics when I have time,

 

[john t]

the data logger

 

[user 6228]

This may be of interest, as for the practical use im not sure but welcome comments.
I have been monitoring the internal hive temperature /humidity using a small data logger, I have placed the device in the hive inside a sock, it was placed on the top bars which are covered with insulating material, the device logs the temperature and humidity and dew point at intervals which I have set to record every hour.

The device is called a TEMPO DISC™ Bluetooth wireless thermometer purchased from amazon £40 It is the size of a 50 p coin, and connects to your phone via Bluetooth, so I can download the data without disturbing the hive, the temp/humidity /dew point readings can then be emailed from the phone as a doc and used in a spreadsheet, it also produces graphs and can send alerts so all in all quite a powerful bit of kit,

I placed the tempo disc in the hive at the end of February before I went away on my holls, and downloaded the data the other day on my return, the temp that I recorded ranged from 12 c to 22c unfortunately as I was away I wasn’t able to record the outside temps but it was well below freezing for quite a few days and snowed in Hampshire

Example of data downloaded :- Time 12:00 24/02/2018
Temp =14.1c
Humidity = 75%
Dew point = 9.9c

One observation I have noted is that the hive temperature is always about 6 to 8 deg c above the dew point, I will take some external temperature readings together with internal readings to compare and post at another time, I intend to leave the device in the hive throughout the coming season and will try to add more info if anyone is interested and post some pics when I have time,

A general observation of hive temperature measurements by anyone
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To get something worthwhile from hive temperature readings, you have to have a clear idea of what you are trying to achieve, the thermal properties of the hive enclosure and contents, and place the temperature sensors accordingly. To do this you will need to have at least a basic understanding of heat transfer. Without this you can fall into a trap of measuring almost nothing of real value. A trap that has collected many academics (including graduate engineers) as well as enthusiasts.
As an example you have an observation
" hive temperature is always about 6 to 8 deg c above the dew point"
this can mean one or none of :

• Honeybee temperature regulation
• honeybee humidity regulation
• efficiency of the hive as a dehumidifier
• Heat loss of the hive
• faulty sensor

The thermal environment of honeybee nests is complex. A complexity which increases my admiration of the honey bees.

 

[Finman]

.
When I read this, I got into mind that there is no data, what terrarium heater on the floor affects on temperature of the brood box. I have used 6W to 15 W heaters. OK, I will use normal on out digital thermometers to measure the corner temps of the the hive. What the terrarium heaters do is, that area of the brood will cover the whole frame, from corner to corner.

But only heat does not make brood. Bees need proper protein in brood rearing.

 

[Poly Hive]

A couple of days ago I was told a "fact".

This was that if bees are "properly insulated" the only colonies that actually cluster are in the far Northern climates.

Derek?

PH

 

[Finman]

A couple of days ago I was told a "fact".

This was that if bees are "properly insulated" the only colonies that actually cluster are in the far Northern climates.

Derek?

PH

Such fact there...

When I live here in North, and out temps are about +6 - 0 C, bees make a cluster.

in -10 C out temp cluster is very tight and it is impossible to quess, how much there are actually bees. Part of cluster is inside empty cells.

But what do you do with that "clustering knowledge". It is bettar that you do not peep into hives during winter and wonder that clustering. You can only disturb the bees.

 

[user 6228]

A couple of days ago I was told a "fact".

This was that if bees are "properly insulated" the only colonies that actually cluster are in the far Northern climates.

Derek?

PH

All i can say that in a tree level of insulation "external temperature forced" clustering does not occur.
That is to say the level of heat production and their honey reserves are sufficient not to cluster all winter within a nest with the same level of thermal conductance as a tree nest at external temperatures below -40C.
External Temperature forced clustering occurs when the energy expenditure required to maintain a non clustered state exceeds a sustainable level (perhaps 25W/kg)


However, having observed honey bees, in a tree level insulated nest, not in cluster in external temperatures at -13C and in cluster at +5C, it is clear that honey bees can elect to be in cluster for other reasons than external temperature in a well insulated nest.

Such a reason is energy conservation. Honeybees cannot know how long the winter will be, so a behaviour that conserves energy when there is no advantage to expending it, confers a survival advantage.

 

[john t]

as i first mentioned im not sure if this data will be of any use, but i do find doing practical experiments fascinating,far better to do it for real than reading about it ,
it is early days and i can see that monitoring the outside temp to compare with the inside temp would be helpful ,
and as the device is sitting on the top bars under an insulated cover the readings will be limited to just that area above the brood nest / cluster ,maybe later on in the season i might think about placing the device in the center of the nest,

as Derekm says "The thermal environment of honeybee nests is complex"

at the moment for me it is immaterial the type of hive, mine is a national wood construction , all i can see is that the temperatures fluctuate throughout the day/night i can see the max and min temps and humidity, it would be interesting to compare other hives

 

[user 6228]

Statements of form "Honey bees make no attempt to heat the hive when packed/insulated." are often used to infer that honeybees have no use for insulation.
Alas all this does illustrate that they underestimate their honeybees, because the effects of the cluster and the hive are additive.

What that means.

If you halve the thermal conductance of the hive, then for the bees in cluster to let the temperature inside drop back to old level, then they must halve their heat production and honey consumption.

 

[Apiarisnt]

My crude but useful temperature monitoring..

My first colony was a caught in a bait hive in July 2016 ( so not worth a fly). I cosseted it with plenty of feed and 100mm of insulation all round, but was fearful this it might nonetheless die in the winter. Wanting to know whether it was still alive but not wanting to open it up in the winter, I stuffed a thermocouple on the end of a wire roughly in the middle of the hive and checked it every day or two. (The colony survived)

I expanded with three more colonies last year and stuffed crude thermocouples into each of them. It has been fascinating to watch the temperature variations through the season.

I realise that measuring the temperature this way does not constitute proper temperature monitoring. Changes in the readings could just be the cluster shifting around, and every time I inspect the hive in the summer the thermocouple inevitably never goes back in exactly the same position.

Nevertheless I have found the information logged informative and useful in assessing and comparing how the colonies are progressing. It also still fulfils its primary purpose of establishing whether the colony has snuffed it or not.

 

[john t]

we had 3" snow overnight (18/03/2018) and in the morning i was able to record the ambient temperatures as well as the internal hive temps i was surprised how low it had recorded 7 deg c

at the time of recording

ambient temp = 5 deg c
hive internal temp = 8 deg c

i had to remove the sensor from under the quilt there was still quite a bit of movement on the top bars

 

[TooBee...]

As an example you have an observation
" hive temperature is always about 6 to 8 deg c above the dew point"
this can mean one or none of :

• Honeybee temperature regulation
• honeybee humidity regulation
• efficiency of the hive as a dehumidifier
• Heat loss of the hive
• faulty sensor

The thermal environment of honeybee nests is complex. A complexity which increases my admiration of the honey bees.

Hi DerekM

am I correct in understanding "dew point" in that as long as the temperature of the air does not drop to the dew point temperature, 9.9c here in this case, then condensation will not form on the walls?

I suspect there may be more to it than I am first seeing here?

 

[user 6228]

you need to measure the lowest temperature air . That is best done by measuring a surface temperature.

 

[Finman]

Bees stand very well different kind of condensation. No need to upset every time if you see it.
.
You may measure many temperatures inside hive box. What you do with those figures, I do not know.

Most condensation happens under the cluster near entrance. What then, nothing. Freezed water will melt when spring comes.

I have had 30 years my wintering hive construction, and it works fine. No need to change it.

But thete are different floor material, which make different amount on condentation in summer. And then moist surface gather dirty and generates mold. Natural wood or natural plywood are worst.
.

 

[TooBee...]

you need to measure the lowest temperature air . That is best done by measuring a surface temperature.

Hi
If the thermal conductivity of the surface material (the inside walls of the hive) was very low, that would impede condensation forming? Is that right?

On a similar note, wooden hives which have had their internal surfaces roughed up are more propolised by the bees than smoother ones (I would imagine the inside of a hollow tree trunk would be quite rough), this has been shown to assist the bees in dealing with bacteria and viral issues, would the propolis not increase the likelihood of condensation as I assume it has a higher thermal conductivity, with it being denser?

 

[TooBee...]

But thete are different floor material, which make different amount on condentation in summer. And then moist surface gather dirty and generates mold. Natural wood or natural plywood are worst.
.

What floor material do you use in your hives? And how do you clean it each spring?

Do you use a plastic sheet, like a varroa tray and just sterilize it? Or do you add an absorbent material like straw and dispose of it regularly?

 

[Finman]

What floor material do you use in your hives? And how do you clean it each spring?

Do you use a plastic sheet, like a varroa tray and just sterilize it? Or do you add an absorbent material like straw and dispose of it regularly?

- floor is coated plywood, 6 mm

- no varroa tray, no plastic sheet

- no absorbent material. Floor is slanting and water drills out.

I clear the solid floor after winter and bees cleant other times.

Absorbent = gathers water and rottens. Never heard about such.

 

[user 6228]

Hi
If the thermal conductivity of the surface material (the inside walls of the hive) was very low, that would impede condensation forming? Is that right?

On a similar note, wooden hives which have had their internal surfaces roughed up are more propolised by the bees than smoother ones (I would imagine the inside of a hollow tree trunk would be quite rough), this has been shown to assist the bees in dealing with bacteria and viral issues, would the propolis not increase the likelihood of condensation as I assume it has a higher thermal conductivity, with it being denser?

Yes because the low thermal conductivity would make for a higher surface temperature,

No. the thermal resistances(resistance is the reciprocal to conductance) add up. So additional coatings increase resistance and therefore reduce conductivity. There may be effects due reduction of surface roughness.

 

[Beefriendly]

Taking the detailed science aside....is there a practical issue involved?

 

[Finman]

.
The most important thing in this issue is colony size, how it stands weather.

It is same, what happens in nature. Varroa kills however every colony without treatment. And a new swarm fills the cavity.

Varroa reduces colony size and then kills it.

You can see all this under your eyes.
.

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