- #1
siri.satyam
- 2
- 0
Why water heated with electric heater remains hot for long time than water heated by gas stove
Why water heated with electric heater remains hot for long time?
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Discussion Overview
The discussion centers on why water heated with an electric heater remains hot for a longer duration compared to water heated by a gas stove. It explores factors such as insulation, heat retention, and cooking methods, incorporating both theoretical and practical perspectives.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Conceptual clarification
Main Points Raised
- Some participants suggest that the insulation of electric water tanks contributes to heat retention, as they are typically well lagged.
- Others argue that the larger quantity of water in a hot water tank results in a lower rate of temperature drop due to reduced surface area for heat loss compared to smaller quantities in kettles.
- One participant notes that using a kettle may be more efficient in certain scenarios, such as when only small amounts of hot water are needed quickly, reducing energy waste from heating larger volumes unnecessarily.
- Another viewpoint mentions that electric heater elements take longer to cool down, which may continue to heat the water even after the power is turned off, unlike gas burners that stop heating immediately.
- A participant raises a question about the heating time of electric elements, indicating that this factor should also be considered in the discussion.
- One participant shares a personal cooking experience, contrasting the immediate cooling of gas burners with the sustained heat of electric burners.
- Another participant discusses the specific heat of materials used in cooking, such as steel woks, and how this affects heat retention, particularly in different cooking styles like Chinese cooking versus European stews.
Areas of Agreement / Disagreement
Participants present multiple competing views on the factors affecting heat retention in water heated by electric versus gas methods. There is no consensus on a single explanation, and the discussion remains unresolved.
Contextual Notes
Participants mention various assumptions regarding insulation, heat capacity, and cooking methods, but these factors are not fully explored or quantified, leaving some aspects of the discussion open to interpretation.
- #2
sophiecentaur
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Two main reasons.
1. The water tank is usually well insulated (lagged).
2. The quantity in a hot water tank is much larger than the quantity in a kettle. Because the surface area (for heat loss) is much less per litre in a big tank, temperature falls at a lower rate.
There is one way in which using a kettle / pot may be better value, though. When you 'run' the water for several seconds from a hot water tap, before it gets warm enough to use, the pipes need to get full of hot water (possibly several litres). This may well cool down before you need any more so you will have wasted the energy used to heat it. If you just heat up 2l of water in a kettle and use it all quickly, there is no such loss.
1. The water tank is usually well insulated (lagged).
2. The quantity in a hot water tank is much larger than the quantity in a kettle. Because the surface area (for heat loss) is much less per litre in a big tank, temperature falls at a lower rate.
There is one way in which using a kettle / pot may be better value, though. When you 'run' the water for several seconds from a hot water tap, before it gets warm enough to use, the pipes need to get full of hot water (possibly several litres). This may well cool down before you need any more so you will have wasted the energy used to heat it. If you just heat up 2l of water in a kettle and use it all quickly, there is no such loss.
- #3
yungman
- 5,741
- 291
Because the heater element take longer to cool down, the pot have direct contact and it keep heating the water for a little while. For a gas burner, the moment you turn off the gas, no more direct contact with the pot and so it cool faster.
That's why when I cook noodles, I turn off the electric burner a minute before the noodle is ready and let the remaining heat keep cooking without using any power...I am cheap.
That's why when I cook noodles, I turn off the electric burner a minute before the noodle is ready and let the remaining heat keep cooking without using any power...I am cheap.
- #4
sophiecentaur
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And how much longer does the electric element take to heat up. One needs to address the relevant factors.
- #5
yungman
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Well, being stuck with the electric burner, you make the best out of it. I am a Chinese, when I really cook, I have my 60,000BTU giant propane burner to cook Chinese food. The frame has to wrap around the wok, food has to catch on fire to frame out to get the essence of Chinese saute cooking!
But still, with the big burner, once you turn it off, it immediately stop cooking.
But still, with the big burner, once you turn it off, it immediately stop cooking.
- #6
sophiecentaur
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Steel (the wok) doesn't have a particularly high specific heat and the essence of chinese cooking seems to be to cook small quantities at a time. So there isn't a lot of thermal capacity there. Any water in the wok that is above 100C will boil off (without a lid) and that uses a lot of latent heat. These are all good reasons why the temperature drops fairly fast.
Contrast this with a good old European Stew in which there is a large quantity of liquid in a covered pot. It will stay cooking for quite some time once the heat is removed.
Contrast this with a good old European Stew in which there is a large quantity of liquid in a covered pot. It will stay cooking for quite some time once the heat is removed.