Hot Water: Difference between revisions
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<html> <iframe src="https://docs.google.com/presentation/d/e/2PACX-1vRJilbmU23TsndNi7tf8qn9vVJRYs_ISeKfr_p3Rjd0xepu5UorTyERm-KsgbSKWmdVgXh4aJ_kMlVy/embed?start=false&loop=false&delayms=3000" frameborder="0" width="480" height="389" allowfullscreen="true" mozallowfullscreen="true" webkitallowfullscreen="true"></iframe> </html> | |||
[https://docs.google.com/presentation/d/1QZGbNQ8sZEjTb_gkaIhhKj7mR1da9iKVamLhAqAEhZE/edit#slide=id.gb328b2d63d_0_9 edit] | |||
*Pain threshold for a human is 106F [https://1800anytyme.com/blog/how-water-how-hot-is-too-hot/] | *Pain threshold for a human is 106F [https://1800anytyme.com/blog/how-water-how-hot-is-too-hot/] | ||
*If water is 60F year round from a supply - does 39F rise (see [[Tankless Electric Water Heater]]) suffice? | *If water is 60F year round from a supply - does 39F rise (see [[Tankless Electric Water Heater]]) suffice? | ||
| Line 14: | Line 18: | ||
*this can be alleviated with a tank kept at room temperature inside the house. | *this can be alleviated with a tank kept at room temperature inside the house. | ||
*Design around Bricor 0.625 gpm shower head. [https://www.bricor.com/products/ultramax/] | *Design around Bricor 0.625 gpm shower head. [https://www.bricor.com/products/ultramax/] | ||
*Assume house temp is 68-78F [https://www.google.com/search?sxsrf=ALeKk026QG9BbsZl0rNsBS9KmerMgczY_w%3A1602863734253&source=hp&ei=dsKJX6q8DJDYsAXHkpG4Cw&q=comfortable+house+temperature&btnK=Google+Search&oq=how+to+configure+nvidia+geforce+gtx+1650+super+on+linux+mint&gs_lcp=CgZwc3ktYWIQAzIFCCEQoAEyBQghEKsCMgUIIRCrAjoOCAAQ6gIQtAIQmgEQ5QI6DgguELEDEMcBEKMCEJMCOggILhDHARCvAToLCC4QsQMQxwEQowI6CAgAELEDEIMBOggILhCxAxCDAToFCAAQsQM6AggAOgQIABAKOgYIABAWEB46CAghEBYQHRAeOgcIIRAKEKABUMsQWOmzAWD8tAFoBnAAeACAAeQGiAGhS5IBDTExLjQ3LjMuMi42LTGYAQCgAQGqAQdnd3Mtd2l6sAEG&sclient=psy-ab&ved=0ahUKEwiqz4DcvLnsAhUQLKwKHUdJBLcQ4dUDCAk&uact=5] | |||
*'''Assuming that house temperature is 68F and up all year - use this ambient temperature to preheat water by leaving a water tank exposed to this temperature. This can effectively almost halve the heating energy use for water.''' | |||
*0.32 gpm flow from a 1.8 kw heater which produces 39F temp rise - gets us from 68 to 107F. If we dilute this half way - then we have 19.5 rise from 68 - or 87.5F. Marginal for comfort, we could use more heat. | |||
=Links= | |||
*[[Water Heating Calculator]] | |||
*[[Tankless Electric Water Heater]] | |||
Latest revision as of 22:23, 5 March 2021
- Pain threshold for a human is 106F [1]
- If water is 60F year round from a supply - does 39F rise (see Tankless Electric Water Heater) suffice?
- 60+39= 99F.
- Average shower temp is 105F [2]
- This article says that 99F is better, so you potentially avoid eczema
- It appears that 120F water is a relic of long piping - the hotter the temp the quicker your water will get warm. But for on-demand, lower temperatures appear to be better.
- Thus - minimize piping length to point of use. [[Seed Eco-Home specification is keeping heater distance to within 4' of point of use.
- Tap water is 40-70F if coming from a well - depending on USA location - [3]. Varies for surface water.
- Ground temperature varies significantly with seasons, unless you are 30' deep. [4]
- Earth temperature is constant 30' below surface - this is called the mean earth temp. [5].
- Earth temp varies significantly with seasons - to full seasonal variation - at surface. [6], Thus, water pipes, at 3' or so below, show large variation of seasonal temperature.
- Human body is 98-100F.
Anything higher than body temp feels warm.. No, it's about the temperature of the skin - which is around 32C (90F). Thus, the absolute minimum shower temp must be 90F for it not to be uncomfortable. [7]. From [8] - If 90 is minimum acceptable, then minimum ground temperature of water must be 51F.
- this can be alleviated with a tank kept at room temperature inside the house.
- Design around Bricor 0.625 gpm shower head. [9]
- Assume house temp is 68-78F [10]
- Assuming that house temperature is 68F and up all year - use this ambient temperature to preheat water by leaving a water tank exposed to this temperature. This can effectively almost halve the heating energy use for water.
- 0.32 gpm flow from a 1.8 kw heater which produces 39F temp rise - gets us from 68 to 107F. If we dilute this half way - then we have 19.5 rise from 68 - or 87.5F. Marginal for comfort, we could use more heat.