Power is Voltage times Current, and power consumption is measured by Power times Time.
Note that your CRT's specs show that it will draw one of two currents depending on your location's mains voltage. If your area uses 120V AC, your CRT will draw a maximum of 1.5A; if your area uses 220V AC, your CRT will draw a maximum of 0.8A.
Power consumption for 1 hour:
= Voltage * Current * Time
= 220 V * 0.8 A * 1 hour = 176 Watt-hour
= 176 / 1000 = 0.176 Kilo Watt-hour
To find the consumption for one day, multiply by 24:
0.176 * 24 = 4.224 kiloWatt-hours
This assumes that the monitor is on for all 24-hours. If the CRT is under standby mode, then the power consumption will be lower.