Essay on Human-Powered Gym

What follows is another assignment: this time a 1,700 word discussion of the human-powered gym concept. It's basically a formal writeup of the two posts I made on this back in August. Enjoy!

Human powered gyms

As we increasingly look for alternative sources of energy, could there be an untapped potential power plant within each of us? David Pickup examines the possibility and economics of a human-powered gym.

25% Renewable Energy is Achievable

First, an apology. I have been ridiculously busy with uni work over the last month or so, so haven't done any posts- sorry for that.
I recently wrote a persuasive writing article for one of my modules on "25% Renewable Energy is Achievable" (I'm arguing that it is achievable) and so here it is, in all of its 1,500 word glory! Enjoy.

Personal Transport: Different Types

  I drove back from uni the other day, and on the way I thought about different types of transportation. On this trip, for example, I only took back a few bags, but on the trip up, I had a carful of stuff. I also saw many different sizes and shapes of 'cars'- vans, lorries, little hatchbacks (like mine), family saloons, campervans and big 4x4s. These varied vehicle designs are made to do different things: a small hatchback is not designed to carry the same volume of stuff as a big 4x4, for example, but it is more fuel-efficient (as the 4x4 engine is bigger to cart around a bigger car). Most cars built nowadays are multipurpose.
In this post I'm going to talk about the different needs of the varied vehicles on the road today. These needs include range, top speed, and acceleration. Obviously, a city runabout doesn't need to have the range or top speed of a long range cruiser.

The most important part of the 'car' is the engine: what makes it go. Pretty much all engines out there on the roads are internal combustion engines, which use petrol or diesel to explode a gaseous mixture of the oil fumes and air, pushing down a piston, turning a crankshank, which turns the wheels. I'm not going to go into detail into how these car engines work, but see here if you are interested. This is all very well, and has been working around the world for over 100 years. However, these engines are very inefficient, by modern standards: 20-30% (from wikipedia). Compare this to a electric engine, for example, which has an efficiency of around 90% from batteries (source- this excellent page by the Tesla Motors Company, which has a lot of other information about efficiency as well) or about 60%  from a hydrogen fuel cell (source) [*]. Add this to the fact that the fossil fuels used in the internal combustion engine are both producing greenhouse gases (CO2) and are running out, and you can see why it's worth considering other options for our transport.

[*]- Note that both battery-powered and fuel cell-powered cars use electric motors, but different methods to store the electricity (in the battery or hydrogen).

 So what different types of vehicle are there? What designs do we need to use, and which type of power would be best for each?

Personal Transport: Examining My Trips

I think it would be interesting to examine the different trips I make in my car (which, I am ashamed to admit, I do quite a lot of), and see if I can change my habits to do less driving, saving money (hopefully) and using less petrol (good for the environment!). This is something anyone could do easily, so I encourage you to do the same after reading this post- you may be surprised at how easily you could save money and do a bit to help the environment.

The Trips

I'm going to take the last year as a typical year for me as a typical 20 year old student. I admit that this state of affairs is not the global average, but I do think that the system of commuting (to and from campus), with 6 long trips a year (uni to home and back) is one that can be very simply adapted to a professional lifestyle. The commuting trips are similar, and the long trips could be travelling somewhere for a holiday (going somewhere for christmas, for example). The main difference is the holidays, which means I'm not commuting to uni (work) 5 days a week for about 4 months in the year.
 Let's now examine my different trips.

Human Powered Gym- Part 2

In Part 1 we examined the use of cardio machines (specifically a exercise bike) to generate electricity to power various items in the gym.
The conclusion of Part 1 was that a normal gym goer could power the machine, charge his phone and maybe power a light or two. Alternatively, he could power the machine and the stereo system.

That's for one person. What about if we have loads of machines, with some being used by people at a certain time, and others not (i.e a gym)?
Let's take the gym I go to as an example. It's a relatively small gym, with 6 upright bikes, 2 recumbant bikes (which I will regard as equivalent for the energy-generating purpose), 8 treadmills, 6 cross-trainers and 4 rowing machines, along with various weights machines and free weights.

If all of the bikes are used at the same time (they never are, but let's assume) then the total power being produced will be 56 x 8 = 448W.                                  [This 56W value comes from Part 1]

 However, I reckon that on average only about half of the machines are used at any one time. This means that we have half the power (224W) to use.


This will be just about enough to power the 4 machines (80?W), light up some of the gym (assuming 4 20W fluorescent tubes, 80W), power the music system (which is probably more than 30W as there are quite a few speakers- 50W?) and charge any gadgets the users want to (maximum of 8W).

Hang on, I hear you cry- what about the other machines?

Human Powered Gym?- Part 1

I was in the gym the other day, when I thought "hang on a minute, I'm on a cycling machine, which is just basically making a wheel turn (the basis of electricity generation). Why can't we use this to power the gym- lights, the tvs, the radio, the air conditioning and the machines themselves?"

I suppose a more reasonable question is:
Is it economically viable to install generators attached to the machines in a gym? Noting that:

1.  Almost certainly new exercise equipment would be required.
2. All the machines aren't going to be used all time, so either you need a backup supply system (if the average energy output isn't as large as the energy requirement) or a method of storing the energy (if the average energy is larger than the energy requirement).
3. Generators require something spinning, preferably constantly. This is fine on a bike, but rowing machines, treadmills and cross-trainers won't be quite as simple.

 As I imagined, I am not the first person to think of this idea (nice as it would have been!). In fact, there is a gym in Portland across the pond which does exactly this:

http://news.bbc.co.uk/1/hi/technology/7796215.stm

There are also gyms in Hong Kong using this concept:

http://www.inhabitat.com/2007/03/08/human-powered-gyms-in-hong-kong/

And, as a blue sky "gym concept" island:


http://www.alternative-energy-news.info/human-powered-workout-gym-concept/

For this last article, I am not so interested in the article itself, but the comments after it.

This is all very interesting, but let's examine (using the figures found on the companies websites, as well as other sources I will mention) the actual numbers.

Introduction

The Issue- Energy.

We all use it, we all need it. At the moment though, we are developing more and more energy-intensive processes: not just the increasingly powerful gadgets that adorn the local technology shops in all their forms, but also heating/cooling, commercial uses (including making the materials needed for those gadgets!), transport, massive data centres and many more. With these increases in electricity usage, we will need, both in the short and long term, better processes to generate electricity.

The purpose of this blog is to explore different ways to approach the problem of energy for the future. This will range from the very small (a smart grid for the home?) to the very large (how about using electric car batteries to store surplus electricity?). I will also think about transport, both for people and freight.

I am a university undergraduate, and as such not an expert in this field. What I lack in in-depth knowledge, however, I make up in enthusiasm, problem solving and ideas. Because of this, I would greatly appreciate any feedback on any ideas contained within this blog- whether it is a company director of a power meter I am testing or just a interested reader.

I have many ideas already on things to write about, so I'll get working on it!