Glycol reticulation

Hi guys,

We have been installing glycol reticulation systems for breweries and vineyards here in New Zealand for a number of years now. To date, our systems are simple, effective and reliable but I can't help but think there'll be frigies around the world building better, more efficient plants and i'm basically reaching out for better ideas.
Our systems are simply a Refrigeration plant, chilling monopropylene glycol through a plate heat exchange, the glycol is stored in an insulated tank, from there it is pumped out to the various wine/beer tanks. We usually use a simple solenoid on each tank controlled by individual thermostats. We have a bypass at the end of the run on the main line set to a minimum setting to keep the pump happy in the event of all tanks at set point.
We will often use the glycol to run through an air handler for a cool room onsite.
We will always try to convince the customer to opt for an electronic expansion valve on the unit, we haven't used TXV's on these plants for some time (I think all refrigeration gear should be on EEV's)

I know this set up is quite standard and very simple, I know there must be much better ideas out there.

I have a plant I am working on a design for at the moment, a meat processing plant.
The site is 90% medium and high temp. At present the site has around 25 evaps, running on R404a, two 70hp Frascolds running the medium temp rooms (0-2 degrees C) and one 75hp frascold running the high temp areas (6-10 degrees C).
Due to the ever increasing cost of refrigerants and the plant in need of an up grade, we see glycol reticulation a good option.

My thoughts at the moment is one common ring main, a 3 way valve at each air handler and a VSD driven pump pushing the glycol.

I want to eventually utilise the existing compressors but as we need to keep the entire site running during the upgrade I think we'll run the ring main, install the glycol tank and all required pumps, install a stage one refrigeration plant that will be bought new (maybe transcritical CO2), then as the site is converted we should get to a point we can add another heat exchanger and run the frascolds through that to take up the load.
Later on we will probably scrap the frascolds and throw another CO2 plant at it.
We will also add a heat recovery system of some description.

Is there any literature floating around on current desgins people are using, how systems are being controlled? etc. I'm happy to hear anyone's input. There isn't a lot around this topic on design on the internet. I realise it's nothing knew but I bet there's some awesome ideas out there. I want to build , reliable, a energy efficient plant that's future proofed for a good while to come.

Thanks