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Heat people, not spaces (2015)

solar.lowtechmagazine.com

51–60 of 335 posts

Re: Heat people, not spaces (2015)

#51

We take the general concept of heating people, not the space, to heart for our outdoor swimming pool. While most other folks heat their pool, we go ahead and swim in the cold water... but we buy everyone in the family a wetsuit. A few hundred dollars on wetsuits each year is far better than many hundreds on propane every month.

That seems like it entirely defeats the purpose of a pool.

Re: Heat people, not spaces (2015)

#52
post #41

Earlier quoted context omitted.

Uhm.. for me it helps, and A LOT. Surely there are more factors involved, which I'm not aware of. I'm talking from Fortaleza, Brazil. Maybe the sea is bringing cooler air. I really don't know, I only have these pieces of empirical knowledge and my experience is very narrow, basically limited to this city.

A large body of water near by certainly has a moderating effect on temperature. I looked up the climate data for Fortaleza, and compared it to my town (random US city, about 35 degrees northern latitude, so not super far south or anything.) Our average daily highs in summer are only about 1 degree (C) lower than your RECORD highs... your averages are about 9C lower than ours. Without AC here it would be...supremely u…

Our air masses are probably cooler than yours because of the sea, I'm not sure. There seems to be more factors in operation.

Re: Heat people, not spaces (2015)

#53

Earlier quoted context omitted.

I've spent a lot of time in very old houses with limited to no modern heating, and I've never experienced this. The biggest indicator for mold is moisture trapped between walls (including animals getting stuck in walls and dying). But that's a water and humidity thing, not an ambient temperature thing.

I think some very old houses don't have mold issues because they aren't tight enough . You get so much airflow through the walls, they don't really get damp. Source: lived in a ~100 year old house in the Midwest for 15 years or so. The only place we got mold that I remember was inside the air conditioning unit.

Reminds me of when my mother had her kitchen renovated. When they removed the lathe & plaster, you could see the road clearly, right through all the slats. From outside they look tight, but they are anything but.

Re: Heat people, not spaces (2015)

#54

I've been thinking about the inverse problem. I live in a very warm city. Air conditioning (cooling spaces) is the norm, but tons of money are spent with installations, maintenance and the monthly electricity bill. The new houses are designed with zero consideration about ventilation, designers seem to take for granted that you are going to buy an AC system. Oftentimes, a very simple change in the project would be en…

IMO the real solution is building materials with high heat mass (e.g. stone), and architectural designs which allow for passive cooling. This exists already, but can be expensive to build.

An alternative is heating panels that emit long IR. These allow you to maintain a lower air temperature and still be comfortable when they're shining on you.

Re: Heat people, not spaces (2015)

#55

I've been thinking about the inverse problem. I live in a very warm city. Air conditioning (cooling spaces) is the norm, but tons of money are spent with installations, maintenance and the monthly electricity bill. The new houses are designed with zero consideration about ventilation, designers seem to take for granted that you are going to buy an AC system. Oftentimes, a very simple change in the project would be en…

I would disagree with new houses not considering ventilation. There are set building standards (ASHRAE 62.1, 62.2, and ISO standards) that have been around for a while that specify how ventilated spaces should be for given use cases. There’s a more recent trend to evolve these standards to take into consideration non-hazardous levels of particulate matter and gases that still show cognitive impairment—-I’m currently exploring this topic area for my PhD work.

What we’re seeing, though, are tighter building envelopes so that the structure is thermally efficient. However, with a tighter envelope, active/natural ventilation systems becomes even more important than in older structures where there is some rate of natural air exchange with the exterior through building cracks and terrible (by todays standards) windows.

There are companies coming up that are looking at “Personal Comfort Systems” and there is a fair amount of active research in this area (ex., https://cbe.berkeley.edu/research/personal-comfort-system/). It’s an interesting space since you have essentially two knobs to play with: (1) a persons actual heat exchange with the environment and (2) a persons perceived heat exchange.

Re: Heat people, not spaces (2015)

#56

We take the general concept of heating people, not the space, to heart for our outdoor swimming pool. While most other folks heat their pool, we go ahead and swim in the cold water... but we buy everyone in the family a wetsuit. A few hundred dollars on wetsuits each year is far better than many hundreds on propane every month.

I understand the appeal of a swimming pool on a sweltering summer day but if you have to heat it...

In many places, even on a warm summer day the pool may be uncomfortably cold. Lots of thermal inertia, and if it's shaded at all it may not get enough solar energy to warm up. Without a heater the swimming season can be very short indeed.

Also, it's pretty darn awesome to fire up the pool once a year in the winter, like for Christmas, and host a swimming-in-the-snow party. Wouldn't want to keep it heated, but for a couple days it's not too bad.

Re: Heat people, not spaces (2015)

#57
post #41

Earlier quoted context omitted.

Uhm.. for me it helps, and A LOT. Surely there are more factors involved, which I'm not aware of. I'm talking from Fortaleza, Brazil. Maybe the sea is bringing cooler air. I really don't know, I only have these pieces of empirical knowledge and my experience is very narrow, basically limited to this city.

A large body of water near by certainly has a moderating effect on temperature. I looked up the climate data for Fortaleza, and compared it to my town (random US city, about 35 degrees northern latitude, so not super far south or anything.) Our average daily highs in summer are only about 1 degree (C) lower than your RECORD highs... your averages are about 9C lower than ours. Without AC here it would be...supremely u…

This is something that I don't think Europeans appreciate. Most of the USA is way hotter and way colder than most of Europe

Re: Heat people, not spaces (2015)

#58

I've been thinking about the inverse problem. I live in a very warm city. Air conditioning (cooling spaces) is the norm, but tons of money are spent with installations, maintenance and the monthly electricity bill. The new houses are designed with zero consideration about ventilation, designers seem to take for granted that you are going to buy an AC system. Oftentimes, a very simple change in the project would be en…

Ventilation doesn't help much with humidity, which frequently overlaps with the heat. I get by without AC in the northern Midwest, but I'd be inclined to get a window unit if there was more than a few uncomfortable nights a year.

Homes should include a central dehumidifier. I believe they’re more efficient than running the AC since there’s no net temperature change?

Re: Heat people, not spaces (2015)

#59
post #48

Earlier quoted context omitted.

> The new houses are designed with zero consideration about ventilation, designers seem to take for granted that you are going to buy an AC system. These are two separate problems. In the ideal situation, you generally want the house to be fairly air tight and condition the air for (a) temperature and (b) humidity. Each of (a) and (b) are taken care of by different mechanical units: one is monitored by a thermometer…

This is exactly the problem with newer design and construction philosophy. Its premise is that we will use mechanical systems, and then try to make these mechanical systems more efficient such as improving insulation, using multi-stage condensers for the AC, etc. This is epitomized in the passive house concept. In contrast the older philosophy is that natural ventilation is good enough, so we design houses to improve…

Indeed. Speaking about hot and sunny cities like mine, besides strategic placement of windows I would also mention barriers to direct sunlight over the walls. Simple barriers can improve inner temperatures sensibily and costs no energy, but most projects don't take that in consideration.

Jesus, here there are even buildings importing those "glass wall" concepts, which makes total sense in climates like European's and north American's, but makes absolutely no sense in sunny cities -- you just end up aggravating the greenhouse effect and having to rely more heavily on AC. Everything because of façade aesthetics.

Re: Heat people, not spaces (2015)

#60
An issue with keeping yourself warm with clothing is some hotspots get too warm, and others too cold. Like the armpits usually get too warm, but your exposed hands too cold. If your slippers have sheep's wool in them, like ugg slippers, then they often sweat a lot or feel a little wet while simultaneously feeling cold at times, or warm enough. Most sweaters are also not designed to keep your armpits a little bit cooler so you stay evenly warm along your body.

If you want to wear gloves, then finger and hand mobility is effected, and usually with hands, it's the fingers that are cold anyway, making fingerless gloves not feel that useful.

While if the room is all one consistent warm enough temperature, you don't get these cold & hot spot effects.

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