Okay, but where is this 30% jump in efficiency going to come from? That seems like a pretty big leap!
* A lot of home conditioners are fighting the weather in conditions with poor insulation, running when nobody is home, or running in rooms when people are in different parts of the house.
* Office air conditioners are often set too cold, subjectively speaking, sometimes resulting in workers bringing sweaters or even space heaters to their desks. This is shockingly common. Multi-zone cooling can make things more uniform, and if you can get people to stop using space heaters during the summer, that can make a big difference. Gender is supposedly a huge factor in temperature preferences, and offices are set to men's cooler preferences. In some locations this is exacerbated by the fact that men wear suits and ties while the women wear skirts and weather-appropriate tops.
Personally, I want an air conditioner system that isn't set to a specific temperature, but instead reduces the extreme temperatures outside. So instead of keeping it set at 22 degrees, maybe it would be set to 22 degrees when it's 27 degrees out, but the AC goes to 25 degrees when it's 35 degrees out. I find this more comfortable, because there's less of a shock when going outside or coming inside.
It's exacerbated (good word) by the fact that the large front office has mostly women sitting at low-power PCs, the offices are mostly men at powerful workstations (aka space heaters), and the HVAC ducts run though the office drop ceilings, meaning anyone doing physical projects in the central work space is the least cooled while our receptionist has been seen with a space heater.
WFH = less traffic, less industrial building construction, less heating/cooling of empty spaces (offices at night, homes during day), less indoor lighting usage (homes are usually very well lit from outside light while most cubical jungles are lit by fluorescent lighting).
Wanna save the environment? WFH!
A lot of people just leave their computers on (with sleep disabled), just because they don't want to wait 30 sec for the boot or to start their apps.
In one office I worked at, the AC controls were not accessible, and because there was no dress code whatsoever, everyone complained about the temperatures being too low. There was a TI office in the same building, and because everyone was in business casual or higher, they didn't have the same problems.
Designing uniforms which look professional and composed but which also ventilate correctly could considerably raise optimal office temperatures.
Just look at the hoodie pre and post zuckerberg.
If Mark had instead wore a tank-top and board shorts 50% of SF would be wearing that year round instead.
Hoodie and jeans is an okay uniform inside a business (though I would argue that if they're not well-kept, it lowers the standards of the people in the office), but in customer-facing roles I think it's inappropriate. It can be done well, but most hoodies and most pairs of jeans are an aesthetic disappointment, since they're built for casual warmth and gold panning respectively.
I would not trust a bank which faces its customers with hoodies, T-shirts, and jeans. The appropriate attire for a clerk usually involves a shirt (especially with a vest) or one/two tone blouse, and trousers or a skirt. Makes you look kempt, but dynamic. A unifying visual theme for staff also makes it simpler to identify them. If the clerks all have a consistent uniform, the custodial staff a different but thematically matched uniform, it makes it simpler to navigate a customer-facing office. I think Hooters does a good job of this, it is easy to locate and discern the staff from other guests, and contributes to the environment (a casual, consistent dining establishment which has attractive, well-trained, and helpful service staff).
You say that "face customers with hoodies, t-shirts and jeans" except this is exactly hooter's uniforms. everyone wears uniform t-shirts. The non-wait staff wear jeans or shorts (depending on season/climate).
You're just showing off your innate biases based on current fashion. There's nothing innately better about a specific functional form of dress over another. A suit is not inherently more powerful than a Thawb or a Kimono. If we were going for pure power we'd all be in hockey or football pads or suits of armor.
Uniformness you have somthing on. But you can be uniform on just about any type of dress. Hell you can be uniform on color and totaly different on form and it'd still work.
This also might point out that you are basing things on appearance instead of form.
I did not say that, I explicitly said that the quality and fit of the clothing is of primary importance. You could make the argument that the ceiling is much higher for Kimono, they seem to start around ¥200,000 JPY, and going up from there not for the faint of heart. Thawbs are sorta self-limiting, little can genuinely be done for their quality, about as limited as the range for white dress shirts; some have weird things like false lapels.
I wonder how many people have respiratory problems that they chalk up to allergies and whatnot that are actually due to the breathing overly-dry A/C air.
No-one should mind if they have it on 18 in winter and the sun heats the room to 20 in the afternoon, but a heat pump on auto will start cooling to maintain the room at 18.
A less straightforward change for further automation would be to make that temperature depending on the humidity. On a dry day, 28°C is perfectly fine, on a humid day it's way too hot. I can't be bothered to adjust my desired temperature depending on humidity, but a computer could easily do that.
Although to be honest where I live, we wouldn't need it. We never really need to heat and cool on the same day.
On the Lowes.com site they have a specification checkbox for "high/low temperature setting" or something similar on each model's details but it doesn't seem searchable there. I don't see such a feature designation at HomeDepot.com as of right now. Amazon's are mixed depending on the seller and model it seems.
I know Nest lets you set separate heating and cooling points if you do the manual programming instead of letting it autolearn. https://nest.com/support/article/What-is-Heat-Cool-mode EcoBee and Hive I'm sure have similar features.
Having separate heating and cooling setpoints only seems natural for something that automatically switches between heating and cooling.
- http://www.fujitsugeneral.co.nz/heat-pumps
- http://www.mitsubishi-electric.co.nz/heatpump/c/7656/high-wa...
Source?
"Gender differences in thermal comfort and use of thermostats in everyday thermal environments". Building and Environment, Volume 42, Issue 4, April 2007, Pages 1594-1603
The biological reasoning, as I understand it, is that men have a higher ratio of heat-generating muscle than women.
When I first moved to NYC, I was bewildered by all the women walking around with scarves and summer dresses; it was explained to me that this was a strategy to optimize being comfortable in the outdoor heat, and then having something to withstand the frigid offices.
(Personally, I'm of the opinion that one should acclimate to their climate, and folks who hate the heat wouldn't mind it so much if they didn't coddle themselves with AC all the time.)
I agree, to an extent. I mean, bumping the temperature that you can be comfortable in by 10 or 15 degrees is reasonable (up or down). I lived in southern Arizona as a child, where 80 degree nights were heaven after 110 degree days. I'd argue that AC wasn't coddling there, though. "But it's a dry heat" has special meaning for me. AC was usually set around 80 or 85.
During some of those same years, we stayed with family in my Grandparents' house: 2 aging window ACs, 90 degree heat, 90% humidity. We spent most of our time outside and slept in an un-conditioned room with the fan blasting. It's doable, but not my preference. A few weeks certainly wasn't enough to acclimate, and I think after a few years I'd probably still prefer to be in a (somewhat) cooled room.
On the other hand, I lived somewhere cold during my early teens. The home was often around 50 degrees with all the radiators blasting, and we dealt with that too.
https://www.nytimes.com/2015/08/04/science/chilly-at-work-a-...
https://energy.gov/energysaver/geothermal-heat-pumps
The amount of efficiency increase you get depends on the ground temp, which varies by latitude, but I've seen 70% reductions in electricity usage quoted for systems installed in North America.
A side benefit is you no longer have a big, loud heat exchanger running on the side or top of your house. The pump unit for a ground loop can sit inside your garage, it's about the size of two mini-fridges and only emits a quiet hum.
Sidenote: When I bring up ground loop air conditioning in conversation with people, no one has ever heard of it. The technology has a marketing problem. That makes sense in states where electricity is cheap, but in places like California I'm surprised the state hasn't mandated them for new installations and offered tax breaks to give it some momentum.
Also, the ground-source heat-pumps aren't cheap. They are in the $7-10k range - just for the unit - and not many people know how to repair them as they are a bit of a specialty item in the HVAC industry.
1. Drilling the wells is not actually that expensive depending where you are.
For me, 3 300 ft wells, bored, piped, and grouted, was about 5k.
2. The units can be gotten for that price with install.
You need to take into account the fact that they are significantly more efficient at both heating, and cooling, and hot water, over their lifetime.
(also, their specs and submittal data usually have real numbers, giving you mappings from incoming water temperature/etc to EER, not BS numbers like most outdoor air A/C units)
They would also be cheaper if they sold more of them :)
3. The units are much easier to keep working, and pretty much never die. They are made much better than the average heat pump. As for your coils, yeah, doing horizontal loops is not a good plan in most cases, though cheaper.
With the 30% federal tax credit that used to exist, a state tax credit, etc, i paid 10k all told.
I made that back in 2 years (the electric bill in the winter went from 600 a month to 100. Yes, the heat pump was functioning properly)
In areas of the country where well drilling is more common, it's a great option. I wouldn't do it in say, the bay area.
But note: none of the wells have to be that expensive to drill, and in fact, when done during new construction, they are often really cheap.
It's just a matter of, in various parts of the country, limited set of people have well drilling rigs because it's not that common. So part of the cost may be "having some guys drive a well drilling rig 5-6 hours to come handle it"
I have three friends/co-workers that had the systems installed. None were particularly impressed with the average cost savings. They said bills went down, but not dramatically. One person had the whole system redone at the suggestion of another HVAC contractor (saying the first cut many corners) the re-done system wasn't much better.
While they may "pretty much never die" this is basically the "cheap on average, but expensive for the unlucky person" argument. This quickly turns into a prisoner's dilemma. No one buys because of potential repair costs, therefore everyone suffers (from higher bills, and eventually global warming).
Wells are not always an option depending on what your land is sitting on. If you are over a big granite deposit, good luck.
Yeah, i lived near a place where wells were incredibly common, so there were plenty of well drillers. I can believe 30k installed. With the 30% federal tax credit that used to exist, and Maryland's 30% state tax credit, it can be worth it. Now, without the 30% federal tax credit, it's probably only worth it on new home construction.
"I have three friends/co-workers that had the systems installed. None were particularly impressed with the average cost savings. They said bills went down, but not dramatically. One person had the whole system redone at the suggestion of another HVAC contractor (saying the first cut many corners) the re-done system wasn't much better. "
This depends a lot on where you live, the climate, etc. Also how much you are spending on heating/cooling. You know all this. I was in a fairly large house in a climate that seems 90+ summers and ~25-30 winters. This kinda sucks for heat pumps. It's also the case that, as it's become more popular (relatively), there are some crappy untrained contractors looking to make a buck. I definitely did a bunch of research, and talked to a bunch of contractors before doing the system. I think out of 5-6 contractors, 1 was clearly a snake, and 1 didn't really know what they were doing based on the questions i asked. 3 could tell me intricate technical details about the systems (IE one launched into a discussion of the merits of parallel vs series vertical piping and reynolds numbers), etc.
FWIW: I've also meant plenty of happy vertical closed loop people. I haven't met any happy horizontal open or closed loop people.
That said, unlike the air based units[1], all, for example, of the waterfurnace units have detailed submittal that tell you, for a given entering water temperature, what the EER/COP will be, what the pressure drop should be, the leaving air temperature, etc.
http://www.waterfurnace.com/literature/7series/SD2700AN.pdf
Most of these things are easily amenable to sensors. I had an arduino and a bunch of sensors that told me whether the system was performing okay.
After they first flushed the lines, they weren't sure they got everything out of it and told me to try it. So I did, and the measurements told me something was off. System worked, when cooling, water temps were raising too quickly. They ended up digging the manifold back up, and there was a rock in it (terrain is fun!) After redoing the manifold, everything was perfect.
So i can also believe that if you aren't watching the till, you may not know if the system is doing okay. But at least, unlike most random heat pumps, i feel like I could know and track that stuff pretty well. Overall, my system actually overperformed (which means they probably didn't need to go as deep as they did, but such is life).
[1] This data exists, it's just not usually easy to get for air source heat pumps unless you are an installer/technician.
So they do something like:
outlet | | manifold inlet in the ground | a bunch of pipes formed into U's, stuck in very deep vertical holes filled with thermal grout | | manifold outlet in the ground | | inlet
The manifolds look like this: https://www.geohydrosupply.com/index.php/fittings/socket-fus...
If it's done in series, each u-bend connects to a set of two outlets on that manifold. If it's done in parallel, each u-bend connects to a single outlet on each of two manifolds, one in, one out.
Here's a drawing: https://blog.heatspring.com/wp-content/uploads/2012/01/paral...
If you can imagine a really huge refrigerant loop, that's what they are, with water+glycol as the refrigerant going through the pipes. But the water only moves in this loop, it's never going into the ground, etc.
Open loop systems exist, and those are the ones where they are sucking something in one pipe, and pushing it out the other.
Sometimes this is done in a pond, sometimes a well, etc. What happens depends a lot of the design (horizontal, vertical, etc).
Open loops are pretty uncommon.
I'm surprised about the earth movement ruining coils. The installations I've seen pictures of show coils with pretty large radii (maybe 18"), I'd think the earth would have to move a lot to do that, and if it's doing that I'd worry about the foundation. Were these small coils? Is the surface really close to the water table?
We have winter lows below 10F/-10C and summer highs above 85F/30C. But the ground temperature is a relatively uniform 50F - useful for both heating (less important, because natural gas is cheap and efficient) and cooling. It's not so useful when the average temp is above your desired room temp.
In the same vein, rejecting heat to the cooler night air is a lot more efficient than using hot day air.
You can operate a chiller at night and generate a bunch of ice efficiently. During the day, you can melt the ice for cooling at day -- without operating any sort of compressor.
Once the melted water gets higher than the desired chilled water temperature, you can turn on the chiller, but you use the water for heat rejection -- which is still colder than the hot outside air.
http://www.utilitydive.com/news/ice-energy-will-provide-1-mw...
Though the NYTimes article points out that the improvement from AC efficiency is mostly related to peak demand shaving as well, so it serves a similar purpose.
Their commercial page is here:
If you have a one stage furnace - your only option is a one stage AC (vs 2-stage or variable speed AC). You need to upgrade the furnace/blower to take advantage of the more efficient AC model
Mini-Splits are great but much more expensive to purchase (~4k USD per Unit which covers 400-500 sqft). They also don't heat as well as a traditional gas fired furnace.
Heat pumps are probably the way to go in moderate climates but I haven't looked into them in much detail.
http://news.mit.edu/2013/madmec-design-competition-1017
Better summer clothes will help too. I've been pretty impressed by advances in cooling undergarments that are designed to wick away moisture and encourage air flow.
Anyway, all of these seemingly unrelated things contribute to improved AC efficiency.