Why do a lot of grocery stores have both horizontal and vertical open freezer compartments? Why not have doors or something to hold the cold in, isn’t it a giant waste of power? These seem very popular at grocery stores with the notable exception of Super Walmart stores.
One theory I had was that maybe the high turnover items are put in these for convenience, but I’ve never noticed that to be the case(at the store I was at today for instance frozen pizzas and TV dinners were in a freezer with a door and whole seafood and squid for example was not.:p)
Another theory was that they are used as supplements to the air conditioning system in hot areas or summer, but in winter you have the absurd situation where the store is pumping in heat and has a large isle full of open freezers:smack:.
To make things stranger stores often have a mix of open freezers and those with sliding or swing doors, and like I said there seems to be no sense as to what goes where.
What is the reason these are so popular, and are they energy wasters compared to a freezer with a door?
They’re also not as inefficient as they might appear. It’s basic physics that hot air rises and cold air sinks. So those open topped freezer bins actually hold most of their cold air in.
Many of the open front cases like the ones used for milk and cheese have a laminar air curtain across the front which is surprisingly effective at keeping the cold air inside the case.
Ultimately, freezer or refrigerator cases with double-pane insulated glass doors and motion sensors to turn the interior lighting on are the most efficient, but their cost of acquisition is so high that they really only make sense for new builds or a complete store renovation.
I always get …I dunno, a chuckle?.. out of the open topped retail freezers with the heated rail. In the olden days, patrons might have had to touch something cold but we’ve come a long way. All in the name of comfort, right?
Increased sales from making it easier to grab that Greek yoghurt > Increased energy used.
I’ve noticed milk is usually behind doors. You’re going to buy milk whether you need to open a door or not. Also stuff that needs to be really cold, like ice cream.
A local grocery (about 1/2 of a block - the too big to be a mom&pop, too small to compete with the big chains) - had old, vertical reach-in reefer units old and (presumably) hideously inefficient units.
They charged $4.59 for an item Wal-Mart sold for $2.50, big chains about $4.
They tried installing thick, clear vinyl strips (each overlapping the next by a half inch) running vertically. It was no problem to see through them, and a very minor effort to reach between the strips to pick up your selection.
Those were gone within a month or two - presumably they cost more in lost sales than they saved in electricity.
There’s no better way to cool yourself off on a really hot, sticky day than to stick your head really deep in one of those, inhale, and feel your nose-hair freeze!
It’s my understanding that that doesn’t actually cost much energy; air has a low heat capacity, so leaving the door open for a minute or two doesn’t actually let much heat into the fridge.
Oh? I feel a bit better. But don’t they say filling your fridge with air-displacers saves energy since less air escapes when you open the door? So escaping air must carry away some “cold”.
Just a WAG, but I wonder if the act of frequently opening a door creates enough air currents that it actually causes more cold air to escape than if there is no door.
I haven’t heard that actually. What I have heard is that it’s good to keep your fridge full of solid objects as “ballast”; since food and water and such has a much higher heat capacity than air it stabilizes the temperature better than air does.
Lots of warm air entering also. Efficient door units have a fan at the top which draws out the warmer air after the door is closed, and circulation fans turn off when the door is first opened.
What I do is get a pack of cheap disposable cups and fill them with water. Then I stick them in the freezer. The resulting cups of ice act as ballast but I can remove them as needed to make room for actual food.
Open freezers aren’t used to supplement the AC in summer. The unit is removing the heat from the open bin and blowing it out the bottom. Because of the added heat of the motor, heat is added to the store both winter and summer.
I buy packs of bottled water and put them in. They’re all ready to take on an outing, they do a better job of chilling in a cooler than ice, and I can just remove them to make room for something in the freezer.
I heard from previous studies that it doesn’t help much – teenagers (and husbands) would just open the glass door, and still stand there staring at the contents.
I saw study showing something a little different. People did need time to adjust to the idea of not opening the door before looking for things, and the total savings were minimal because transparent doors don’t insulate as well as something foam filled. IIRC a sufficient increase in the cost of electricity would make them impractical when overall cost effectiveness including purchase price was included.
