CIBSE Gain - Explanation of Calculation Results Summary

I have a question for you: I am running a CIBSE Gain calculation using Hevacomp and am having trouble making sense of the gains to the spaces. To see why there are excessive gains, I removed all internal heat gains, both sensible and latent i.e. people, lighting and equipment, from all spaces in the model, however, the results of the cooling load calculation show there are still gains (see screenshot). Could you provide some clarity as to what these gains are caused by?
Also, when I input a casual load gain, why does this change throughout the peak day when it is a constant value?
Kind regards,
John Moloney
Sustainability Engineer
Homan O'Brien • Consulting Engineers
89 Booterstown Avenue Blackrock, Co. Dublin, A94 P2C2, Ireland.
Tel: +353 (01) 2056300 Fax: +353 (01) 2056301
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