Cooling-plant renewal should connect load, hydronic temperatures, heat rejection, electrical capacity, phasing, controls, commissioning, and temporary service.

Start with the decision and the building load

Define why the plant is being studied: equipment failure risk, refrigerant or parts support, capacity, energy and emissions goals, compliance planning, resilience, tenant requirements, operating cost, water use, a building conversion, or a coordinated capital project. Identify the facilities, occupancy, critical areas, operating calendar, comfort or process requirements, ownership horizon, project deadline, available redundancy, and consequence of interrupted heating or cooling.

Reconstruct the load record from design documents, equipment schedules, utility and interval data, trend logs, controls, operator observations, testing, balancing, commissioning, complaints, and known changes in occupancy or use. Separate connected capacity, design peak, observed peak, typical part load, simultaneous heating and cooling, seasonal minimum, and future load. A plant should not be sized or electrified from one utility bill, one peak reading, or the sum of equipment nameplates.

Map the plant, distribution, terminal systems, and dependencies

Document chillers, boilers, heat pumps, heat exchangers, cooling towers or dry coolers, condenser and hydronic loops, pumps, expansion and pressurization, chemical treatment, water makeup and blowdown, storage, valves, strainers, insulation, controls, meters, electrical service, generators where relevant, refrigerants, ventilation, drainage, rigging access, and the systems that reject or recover heat. Record age, capacity, configuration, operating sequence, measured performance, condition, support status, isolation, redundancy, and the evidence available for each component.

Follow the water and control path beyond the plant. Air-handling and terminal coils, reheat, perimeter systems, process loads, domestic hot water, heat tracing, snowmelt, tenant equipment, control valves, bypasses, balancing, pump head, static pressure, water quality, and existing supply and return temperatures can constrain the replacement. A new heat source cannot deliver its expected result if downstream coils require a temperature it cannot efficiently produce or if uncontrolled flow and simultaneous loads remain unresolved.

Test electrification at actual operating temperatures

Develop options around the building’s load shapes and temperature requirements. The pathway may involve a like-for-like chiller, modular plant, air- or water-source heat pumps, heat-recovery chillers, thermal storage, boiler retention for limited peaks or emergency use, distribution-temperature reduction, terminal or coil modifications, envelope and load reduction, domestic-water separation, or a staged hybrid before full electrification. Name the functions each option serves and the conditions under which it does not.

DOE’s commercial-building decarbonization guidance emphasizes that feasibility varies with climate, utility rates, existing systems, and other project conditions. Its thermal-systems guide identifies heat recovery as particularly relevant where meaningful heating and cooling occur at the same time. Use hourly or representative operating data, load calculations, weather and occupancy scenarios, achievable water temperatures, defrost and low-ambient behavior, heat-source and sink availability, redundancy, and control logic to establish the concept before equipment selection becomes the strategy.

Coordinate electrical, refrigerant, heat-rejection, and water consequences

Quantify connected and coincident electrical demand, starting and inrush characteristics, voltage, service and transformer capacity, switchgear and distribution, feeders, protection, metering, emergency or standby expectations, utility process, rate structure, demand management, and the schedule for any upstream work. Electrification can reduce onsite combustion while increasing peak electrical demand; the project needs one coordinated load and utility record rather than separate mechanical and electrical assumptions.

Evaluate refrigerant availability, safety classification, charge, machinery-room requirements, current EPA restrictions, manufacturer pathway, service capability, leak response, and future replacement implications with the responsible design professionals. For water-cooled systems, include tower condition and capacity, plume and siting, water quality, treatment, makeup, blowdown, sewer charges, freeze protection, and drought or supply constraints. GSA’s P100 and FEMP cooling-tower guidance are useful technical references for GSA and federal work; private projects must establish their own applicable requirements and operating basis.

Phase the work without losing building service

Create a sequence by plant component, loop, electrical section, control panel, season, and served area. Identify isolation points, bypasses, drain and refill limits, water treatment, temporary connections, rental equipment capacity, fuel or power, staging and rigging, structural and acoustic work, access, hazardous materials, fire and life-safety interfaces, weather windows, tenant notices, outage approvals, rollback conditions, and the point when the old plant may be removed.

Temporary service is a designed operating state, not a line-item placeholder. State which loads it serves, at what outdoor and building conditions, for how long, with what redundancy, electrical or fuel source, controls, monitoring, alarms, staffing, maintenance, freeze protection, condensate or drainage, and failure response. Connect the plant schedule with electrical energization, utility work, controls migration, envelope or terminal upgrades, equipment delivery, permits, testing, and occupied-building constraints.

Accept the plant as an operating system

Define acceptance from design through seasonal operation: owner requirements, sequences, submittals, factory evidence where relevant, installation checks, flushing and cleaning, water treatment, pressure testing, electrical testing, controls point-to-point checkout, sensor calibration, balancing, equipment startup, capacity and efficiency testing, safeties, alarms, failure modes, staging, heat recovery, low-load behavior, trend review, and integrated functional testing under representative conditions.

Closeout should include current diagrams and sequences, equipment and point lists, balancing and test reports, water-treatment records, refrigerant information, controls databases and backups, trend and alarm definitions, utility and meter records, training, operating procedures, maintenance and warranty requirements, spare parts, issue dispositions, and seasonal or deferred tests. DOE’s EMIS guidance uses chilled-water optimization as an example of system-level control. The owner needs the verified operating intent and data required to keep that optimization understandable after the project team leaves.

Primary sources

Sources and technical references.

Source review current as of September 2, 2026.