OK, things are a little dangerous here. I have my notepad out and I'm doodling, and my thoughts are wandering to refrigeration and air conditioning.

Here's my big question.

How much water (refrigerant) is evaporated from the solution in a Lithium Bromide absorption unit?

Or, in other words, what is the concentration of the "strong solution" and the "weak solution" in the system?

Here's my doodling. I have an application where I need about 20,000 to 24,000 BTUs of cooling. In this application, I have a nearly limitless supply of waste heat from a nearby process. This heat is in the form of fluid at a temperature in the 180F to 200F range (80C to 95C).

I'm thinking that this could be used as a heat source for a Lithium Bromide absorption system.

For the cooling capacity I need, the system will have to evaporate 2.5 to 3 gallons of water per hour (20 to 25 pounds of water, or 9 to 12 Kg if metric is your thing). Actually, I'm not 100% sure of that number, because I base that on BTU's required to boil water at 100°C. I think that number varies some with temperature and pressure, and I haven't looked up the actual number for the vacuum/temperature of evaporation in a Lithium Bromide absorption system. I hope I'm close on that number.

In a conventional system, it's easy to know what the flows will be and what size compressor you need. If you need to evaporate x pounds of R22 in an hour, you a compressor that will move x pounds of R22 in an hour.

With a Lithium Bromide absorption system, you use a "solution pump" to move the solution around. The problem is, the solution contains water that is used as the refrigerant, and more water (probably much more) which is used as a solvent medium for the Lithium Bromide dessicant.

So, I'm curious, if I need 20,000 to 24,000 BTU's of cooling, which equates to 2.5 to 3.0 gallons per hour of refrigerant flow, will I need 5 to 6 gallons per hour of solution flow in the systrem? Or 50 to 60 gallons per hour? Or 250 to 300 gallons per hour?

If half the water in the solution "boils out" as refrigerant, then 5 to 6 gallons per hour of solution flow delivers the required cooling capacity. If only 5% "boils out" as refrigerant, then I need 50 to 60 gallons per hour of solution flow. If only 1% "boils out" as refrigerant, then I need 250 to 300 gallons per hour.

None of the "how it works" diagrams that I've found on the internet show solution concentrations. They just have "diluted solution" and "concentrated solution" or "weak solution" and "strong solution." Without numbers, how can one design a system?

I'm still in the "doodling" stage on this, but if it it feasible, I could develop a prototype or custom system for this.