Turn-key office air-conditioning system design

We are relocating into a new office of roughly 420 square metres spread over two floors, and we want a proper engineering design for the air-conditioning system rather than a handful of split units bolted on room by room. We are looking for an engineer who will start with an honest heat-load calculation: solar gain through the glazed facades by orientation, occupancy heat for up to sixty workstations, heat dissipation from computers, the small server room and lighting, plus infiltration through the entrance. Based on that calculation we expect a recommendation on system type — multi-zone VRF, chiller with fan-coils, or multi-splits — with a clear justification of why it fits our capital and running costs. The design must include a floor-by-floor layout of indoor and outdoor units, routing of refrigerant pipework and graded condensate drains, the power and control schematic, wall-penetration details, and a solution for fresh-air supply and extract from meeting rooms and washrooms. A precise bill of materials is essential — exact models, capacities and quantities — so we can send it to three contractors for tender and compare quotes without ambiguity. Please attach the calculation sheets, not just tidy drawings: we want to understand where every number comes from. Experience with offices and retail spaces is required, and familiarity with ventilation and acoustic standards is a strong plus. We can supply floor plans, ceiling heights and facade information. The timeline is about three to four weeks, paid in stages: concept, working documentation, and the final specification.