Rebuild or Replace VAV dual duct boxes

[sean88]

I'm working on retrofiting an old hospital built in 1972. We are putting together a prelimnary construction budget right now. The space consists of some old operating rooms that have been converted into labs. The old system/current system is dual duct VAV boxes fed from a built up AHU with a hot and cold deck. We are going to rip out the low pressure duct and diffusers and replace them. However, a lot of the boxes have the hot deck inlet shut or disconnected. The lab has a lot of heat generating equipment so it needs cooling more than heating.

My question is, is it cheaper to rebuild or put in a conversion kit that will only allow the hot inlet of the VAV box to open after the cold inlet valve has closed or should we replace the boxes totally with series fan powered boxes with eletric heat?

The existing boxes are Trane.
The hospital is running on a limited budget.

Thanks
Sean

[secorp]

New boxes with DDC controls would be a lot easier to warranty. budget bids usually answer the question for you, they will chose the least costly option.