I want to set up a checking account for use for capital projects expenditures. I don't want my normal P&L reports to reflect these project expenditures. How?

A bank account is just where you store money

If you are building something, then you create an asset account and post the expenses there.  When the item is done and ready for service then you decide what kind of asset it is, fixed asset, long term asset, etc and use a journal entry to move the completed value, debit new asset account, credit old asset account for the balance.

Then at tax time your tax accountant and you decide about selecting section 179 accelerated depreciation or not.