Help analysing data

[Drunkard #1]

Hi all

I've got a 35040 row Excel spreadsheet with electricity readings for 3 phases, every 15 minutes for a year.

I need to extract, on a per month basis, the peak load and the usage during each time block (Peak, Standard, Low).

How do I create a formula to read the date and time in column B and C, and then add the data in columns C, D and E to a specific register? There'll be 36 registers (1 per time block per month). I then need repeat this to get the maximum value sent to a register. There'll be 12 registers for this (1 per month).

It's been a while since I've used Excel for anything more than simple addition. Help.

Thanks.

Edit: Sample data:

01 Jan 10	00:15	41	51	20
01 Jan 10	00:30	40	108	23
01 Jan 10	00:45	43	91	23
01 Jan 10	01:00	46	37	22
01 Jan 10	01:15	46	50	24
01 Jan 10	01:30	37	131	21
01 Jan 10	01:45	45	62	20
01 Jan 10	02:00	41	43	77
01 Jan 10	02:15	224	32	98
01 Jan 10	02:30	151	31	24
01 Jan 10	02:45	52	30	21
01 Jan 10	03:00	51	76	20
01 Jan 10	03:15	45	83	20
01 Jan 10	03:30	46	33	24
01 Jan 10	03:45	45	30	23