My top ten

1 (A long way above the rest) Will it do the job I designed it for.

2 Is it reliable and can you maintain it. (That sounds like two points but it isn't really, if you want that customer to come back for more)

3 Can I make a profit at the price a customer is willing to pay.

4 Is this a good use of my time or would I be more productively employed on something else.

5 Is it an elegant solution to the problem I have been set (This is about personal satisfaction and reflects my priorities only) In this context simple is good. No matter how good your buyer is, he will never have as much impact on the final price of the product as your designer.

6 (From here down the order of the answers is as much about the client's priorities as my own) Is it economic to run? This point is about whole life costs and includes energy efficiency, material usage, plant utility, client's labour input, maintenance, reject rates, waste generation, and final disposal costs.

7 Environmental friendliness. We all live on the planet and have a duty to look after it for future generations. However, today's environmentally friendly could be tomorrows environmental nightmare. Replacing whale oil with kerosene in lighting saved the whales from extinction but heralded the oil economy and global warming. Nuclear power was the saviour of the world before Chernobyl and Three Mile Island. Using sustainable materials is pointless if it dosn,t last as long and you have to do it twice. Yes be environmentally friendly, but with the widest longer term view.

8 Longevity is not an issue. Design the product for as long as it is required. Designing and industrial plant to last 25 years is normal, design a mobile phone to last more than 10 years and the infrastructure to use it will have disappeared.

9 Aesthetics. I design industrial products so how it looks is a low priority for my customers. If I were designing cars or consumer products this would come higher on the list.

10 Novelty. Expecting a client to spend a couple of million on my unproven idea for a new way of making something is difficult. A few have trusted me and reaped the rewards. Thankfully, as yet non have regretted it. It is the clients money and he must have the final say on the degree of novelty included. It is always worth making the suggestion. In situations where you can self fund or get a backer to fund your design. Be sure of your ground, double check your calculations and go for it.

The selection of pump ,pipeline size,etc are energy conservation oriented.practice well in Using pump as turbine for small water fall also is energy conservation measure.Indirect use of water power is also is the same