Can I measure the Solar Constant this way?

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Discussion Overview

The discussion revolves around methods to experimentally measure the Solar Constant, particularly in a cold environment during winter in the Northern Hemisphere. Participants explore various approaches, challenges, and considerations for accurate measurement.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant suggests using a black-colored water bottle to absorb solar energy but questions how to accurately determine the energy absorbed per square meter and the relevant surface area.
  • Another participant proposes using a flat bag, such as a hot water bottle or a sealed plastic bag with water, to simplify area measurement as a rectangle.
  • A different participant recommends researching "pyrheliometers" as a potential DIY solution for measuring solar radiation, indicating that constructing a basic version from everyday materials might be feasible.
  • One participant points out that global solar radiation data is readily available online, suggesting that the original poster might find long-term averages for their location.
  • Another participant mentions the possibility of using equations to estimate incident radiation, although they assume the focus is on experimental determination.
  • A participant clarifies that the Solar Constant is defined outside the atmosphere, while on the surface, it is referred to as irradiance.
  • The original poster confirms their intent to acquire data experimentally rather than searching for existing data.

Areas of Agreement / Disagreement

Participants express various methods and considerations for measuring the Solar Constant, but there is no consensus on a single approach. Multiple competing views and suggestions remain present throughout the discussion.

Contextual Notes

Participants highlight challenges such as isolating the heating element from the cold ground and the accuracy of improvised measurement techniques. There are also references to existing data and methods that may not align with the experimental focus of the original poster.

SimpliciusH
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I need a simple way to measure the Solar Constant in a cold environemt (Norther Hemisphere, this time of year ;) ).While its easy to think of ways in which the Sun can heat up something for you...putting for example a bottle filled with water colored black due to ink doesn't seem like a good way of going about it. How am I supposed to figure out how much energy from the sun per square meter the bottle absorbes? How many joules the bottle warmed up is trivial, but where do I get the surface? Do I just take the surface of the bottle or just the surface directly exposed to sunlight or something entirely different?

Also any ideas on how to isolate whatever I'll be heating? Outside the ground is probably chilled already and will drain energy faster the warmer it will get... reducing the already laughable accuracy.

Sure I think just buying a solar cell and measuring the amps from the thing would be the easiest way, but I think they are quite affordable esp since I'm unlikley to use them for anythign else. This is quite a fun project for a kid but I'm wondering how close you could actually get with improvised gear? Any ideas on how to make measurement easier, more accurate?

Thanks for the responses. :)
 
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Have you considered bag such as a hot water bottle or, if you must have it transparent, a sealed plastic bag with water in it? That way, the bag will lie flat and its area will be that of a rectangle, "width times length".
 
I would suggest searching around for information on a "pyrheliometer". It uses a collimating tube with a black object/disc that it being monitored for temperature. I don't think making a crude one out of everyday objects would be too difficult. If you can't find any good info, let me know and I'll try to explain it a little better.
 
Are you looking for global solar radiation on a horizontal surface in Joules/square meter? That information is generally available on the internet. Search for "Solar radiation data" for the country you are interested in. The US and Canada have solar radiation maps that can give you long term averages by month.
 
He could also use equations to estimate incident radiation (Lui and Jordan, Hay and Davies, etc), but I assumed he wanted to determine things experimentally.
 
The Solar Constant is defined outside the atmosphere. On the surface it may be called irradiance.
 
Thanks for the replies guys. :) And yes I'm not searching for the data, I'm trying to figure out how to acquire it experimentally.
 

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