Thermodynamics of Hive Top Feeders

[DCHoneybees]

This is a question for those with personal experience rather than those with a degree in physics.

With the temperatures in my region hovering around the crucial 50-degree mark I have switched over to syrup (1:1) and fed patties to the bees.  Here is my question for those with experience with hive top feeders:

With a feeder that holds a significant about of syrup, would not the liquid act as a heat sink for the hive, absorbing heat from the hive and from the daytime-sun?  If so, does that mean one could feed syrup earlier in the spring using this type of feeder as the syrup will generally remain above the 50-degree even as the evening temps drop into the 30's or 40's thanks to the bee-generated heat and the energy stored from the daytime temps?

[Finski]

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Upper feeder makes the hive cooler. That is only what I know.
That is why I pour strong syrup 65% into combs and put frames into box and box under wintering box. It takes one week when bees rise up the syrup.  They do not loose the heat from hive.

[BlueBee]

I use hive top feeders, but I don't put large amounts of feed in at a time and hence can't really answer your question based on experience.  However... you know I do love a little physics  ;)

The people who build solar homes often try to use thermal mass to store away heat during the day and release it at night.  Water and wax both have very high thermal heat capacities.  Meaning they can store a lot of heat energy.  That thermal capacity means they take longer to warm up, and longer to cool down.  Using these things will decrease the maximum temp during the day and increase the minimum temp at night.   

The problem is if you have too much thermal mass, you end up with a cool damp environment in the spring.  You'll experience that if you've ever visit the west coast of Michigan in the spring.  The Great Lakes act as our like giant syrup feeders and we are like the bees.  Inland in Michigan we get nice warm short sleeved spring days and people are out playing, however if you go to the west coast (of Michigan), you better take a coat and stay huddled together for warmth.

If you're growing apples, the west coast of Michigan is where you want to be since the huge thermal capacity of the lakes starts to give off heat on cold spring nights.  This keeps the apple blooms from freezing on the coast whereas inland we get more frost.

There is probably a sweet spot in a solar design where you have an optimal thermal capacity in a hive, but I don't know what that is.  Since the wax in the hive already has a lot of thermal capacity, I would agree with Finski that adding more syrup would likely result in a cooler hive overall.  Kind of like making a Great Lake even bigger.

Trot has also talked about the negative effects of thermal capacity in his posts.  You'll read that he reports his hives are sometimes colder inside than it is outside.  He says it can take 72 hours for his hives to warm back up. That would be thermal capacity acting against you.

Sorry for the physics dissertation, I know you didn't ask for it.

[Finski]

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Guys, bees do not get hive heat from sun, they make it themselves.
They have in spring +36C in brood area, even if they have dark night or bright sun or rainy day.

[Acebird]

As a new beek last year we had a hive top feeder on through the winter.  Yeah I know you don't feed in the winter but what the heck did we know the first year.  Anyway the one we had was Styrofoam and that is going to insulate the heat transfer that goes on between the fluid and the outside air.  So most of the heat absorbed into the fluid during the daytime is going to be given up to the outside cover at night and not go into the hive.  The other bad thing that happens is the terrarium effect.  It produces a lot of moisture in the top of the hive.  We will never use that feeder again.

[AllenF]

I have used top feeders before.   I know some days when you check them, the bottom is covered with water.   That tells me that the feeder was cooler than the hive and sweat collected.   But it should hold some heat from the day into the evening also.  I have moved into frame feeders now for all the hives.   Just cheaper.   

[Acebird]

But it should hold some heat from the day into the evening also.

Some heat yes but the fluid has to be hotter than the hive in order to pass heat into the hive.  And the styrofoam bottom will insulate that heat transfer so most of it will go up through the cover which is not insulated (normally).

[Scadsobees]

Personally I don't use my hive top feeder when it is cool out. The bees don't pay much attention to it like they would an inverted jar feeder.

They work awesome on those sunny warm fall days though.  The primary function of hive-top feeders is to help the bees get a ton of sugar put away fast.  In the spring this isn't the primary focus, you want to get them stimulated but not put any away.  An inverted jar of 1:1 will do this nicely.

Rick

[DCHoneybees]

THANKS!  This is all great info.  I have been using inverted jars for my own hives but given their capacity I've been equipping hives that are farther afield the hive top feeder due to their capacity...especially for empty hives to which I will introduce packages.  As those packages will not be installed until mid April, a consistently warm month, I am pleased to hear that the bees will accept the feed readily per Scadsobees experience. 

Jeff.

[Countryboy]

Feeding in cooler springtime temps is the one time I can see using Boardman entrance feeders.  Mix up the syrup, and fill the Boardman with warm syrup.  It's easier for the bees to drink warm syrup than cold.  Since the Boardman doesn't hold much syrup, the bees can often drink quite a bit before it cools down.  As long as the bees are close by, it's not too much of a hassle.

I'm not a big fan of hive-top feeders since they have to be removed to mess with the hive, which can be a pain if they are anywhere near full.

If you are starting packages on drawn comb, you can use a clean fruit tree sprayer to spray the combs full of syrup.  This puts the syrup right where the bees need it and can use it.

[DCHoneybees]

I wish I was installing packages on drawn comb.  It will be a foundation-less set up for most or wax foundation.

[Michael Bush]

We tend to have very chilly nights even when the days are in the 50s.  I've found heating the syrup useful.  I dipper it back out into a bucket, take it in the house and warm it up to a temperature you can still put your finger in and not get burned and then put it back in the feeder.  Of course, that was back when I had four to seven hives.  Now I don't have time for it with 200 hives... and I'm not sure how much value it had anyway... but it will get them to take the syrup.

[backyard warrior]

Countryboy i like your info on those hivetop feeders i have a few i know exactly what you mean about it being a issue when going into the hives  i guess this year im going to get some more pale feeders thanks for the wake up call once again :P

[Brian D. Bray]

A large quantity of syrup such as that normally placed in a hive top feeder quickly becomes a brick of ice just above the cluster.

If one insists on feeding 1:1 syrup this time of year it must be placed in, on, or on top, of the hive while it is still warm and removed as soon as it has cooled to the temperature of the ambiant temperature.  That means feeding in in small quantities.  For this a pint jar and a boardman feeder are hard to beat.   Same thing goes for late fall to top off a hive that might be found deficient of stores.

[Acebird]

A large quantity of syrup such as that normally placed in a hive top feeder quickly becomes a brick of ice just above the cluster.

We didn't know any better.  We were under the impression that the bees heated the hive and would keep the feed in the liquid form.  We will never fall for that one again.
The feeder froze into a brick like you said and when we took it off in warmer weather it turned into a mold and algae pit with some dead bees.