Low temp high humidity conditions. 24 Volt a/c timer.

you can refer to other article of the set in the room before.

I dont think its not a difficult thing to construct it.

I think a microchip, several relayers can be done.

write to me, I can design one circuit for you

$500 for a recycling timer? You have got to be joking (it must be a fancy multifunction control device). There are many standard timer modules on the market from many companies (available at many if not most local electrical wholesales) that will do what you have stated. I have attached a link to one we use below. Repeating on and off times can be independently set between 0.1 seconds to 100 hours with an accuracy of 0.5%.

http://www.crouzet-usa.com/catalog/_ele_timers.shtml

Try the MLR1 17.5mm Chronos 2 repeat cycle timer (about $60 US dollars each). You will need an additional relay or contactor if you want to control a load bigger than 10A. Not an ideal solution for your application, but the large reduction in your system costs may make it your best option over precision temperature monitoring and control (does the customer really want or need a slightly better solution if he/she has to pay twice as much for it).

You could also look at Omron timers H3CR-F Series would do this.

http://www.omron247.com

In the past I have used PLR's {Programmable Logic Relays} to great success to control equipment and they are very cheap. You can down load the software right from the Internet for free and are easy to learn to program. The ones I used are Techo.