Demand Flow projects delivered worldwide across offices, hospitals, data centers and universities.
Reduction in total chilled water system energy usage reported by Siemens.
Total system performance achieved without expensive chiller drive options.
Savings often offset implementation cost in about three years, per Siemens portfolio data.
Figures above are Siemens-reported portfolio results for Demand Flow. Actual performance and economics depend on plant configuration, field conditions, baseline, utility rates and project scope — UCS screens your plant before committing to numbers.
Chillers can account for more than half of a facility’s electricity use, and a poorly maintained chiller may consume roughly 30% more energy than necessary. Most plants are not broken — they are compensating.
Demand Flow optimizes every energy-consuming component under a single set of system algorithms, using Siemens Variable Pressure Curve Logic (VPCL) with variable speed drives on chilled water pumps, condenser water pumps and cooling tower fans. The point is total system kW — not a win in one subsystem paid for by a loss in another.
Optimized staging and sequencing with lead/lag control, fewer start/stops, and stable operation across the load range — without requiring chiller VSDs.
Variable speed pumping matched to real load instead of a fixed pressure setpoint, eliminating the over-pumping that drives low delta-T.
Condenser flow controlled as part of the same strategy so tower and chiller performance are traded against each other deliberately.
Variable speed tower fans and a minimized warm-up cycle, coordinated with condenser water rather than run on an independent setpoint.
Colder water year-round improves AHU coil performance and log mean temperature differential, enabling fan energy reductions in VAV systems.
A bespoke digital twin of your plant evaluates actual performance against modeled performance — going beyond rules-based analytics to surface real, actionable drift.
Owners approve these projects for the utility savings and keep them for everything else. Chilled water system optimization is a holistic application of fundamental thermodynamic principles — it resolves operational problems and lets the plant finally meet design intent.
Siemens states Demand Flow can be retrofitted onto any BACnet-compatible building automation system, regardless of the equipment provider, without disrupting day-to-day business or forcing an automation equipment upgrade. For an owner with a serviceable BAS, that is the difference between a controls project and a capital replacement.
Five stages, in order. Nothing gets promised before the screen, and nothing gets called a success without measurement.
Review plant type, owner goals, existing BAS, equipment, available trend data and project timing.
Confirm the water-cooled chilled water application, the BACnet integration path, controllable devices and data quality.
Define controls architecture, instrumentation and point list, mechanical interfaces, responsibilities, ROM scope and Siemens engagement.
Coordinate installation, programming, safeties, sequences, functional testing, trending and owner training.
Establish the baseline and M&V approach, then select ongoing performance monitoring or Smart Services where appropriate.
If several of these describe your building, a screen is worth an hour of your time.
The right entry point depends on whether you are building new, running an existing plant, or already have Demand Flow installed.
Optimize the whole HVAC operation — build the central plant digital twin, upgrade chilled water equipment as needed and deploy optimized sequences.
Refresh an existing Demand Flow project: rebuild the digital twin, upgrade sequencing and recalibrate sensors where they have drifted.
Periodically re-run the digital twin simulation to assess current performance and identify further efficiency improvements before savings erode.
Plan ahead on a new build or retrofit by installing high-grade chiller and central plant sensors up front — avoiding expensive rework later.
Chilled water optimization gives a mechanical contractor a differentiated, manufacturer-backed option on central plant pursuits — without asking an owner to throw away a serviceable BAS. UCS runs the controls scope. You keep the customer.
A shareable concept brief for the people who have to approve the project, plus the manufacturer source material behind the claims on this page.
Two pages: the concept, the partnership model, the project pathway and the fit indicators. Written to be forwarded to an owner, a facilities director or a mechanical partner.
How UCS delivers Siemens Desigo under Niagara as an official Value Added Partner — and the TALON modernization pathway.
Source basis: Siemens Demand Flow chilled water brochure (09/2024); Siemens Demand Flow operational benefits (03/2015); and the Siemens public Demand Flow product page. Demand Flow is a Siemens offering and a registered trademark of Siemens. This page does not replace project-specific Siemens review, design documents or contractual performance terms.
Chiller plant optimization is the practice of controlling a central chilled-water plant as one system — chillers, chilled-water pumps, condenser-water pumps and cooling-tower fans together — instead of tuning each piece in isolation. Done properly it lowers total plant kW/ton, stabilizes delta-T, reduces equipment runtime and start/stops, and holds space conditions more consistently. UCS delivers it in Colorado using Siemens Demand Flow, a patented whole-plant optimization technology.
Siemens reports typical total-system energy reductions of 20–50% across more than 650 Demand Flow installations worldwide, with measured total system performance as low as 0.33 kW/ton. Your actual result depends on plant configuration, baseline performance, runtime hours, utility rates and project scope — which is why UCS screens a plant and reviews trend data before anyone puts a number on a proposal.
Usually not. Siemens states Demand Flow can be implemented on any BACnet-compatible building automation system regardless of the equipment provider, so a serviceable BAS can often stay in place. That said, BACnet-compatible does not mean plug-and-play: a site evaluation determines the sensors, metering, valves, drives, controller, network and programming changes the plant actually needs.
Low delta-T syndrome is when the temperature difference between chilled-water supply and return collapses, so the plant has to push far more water to deliver the same cooling. It wastes pumping energy, limits deliverable tonnage and drives excess chiller runtime. Whole-plant optimization addresses it directly by rebalancing flow against actual load rather than overdriving pumps to compensate for it.
Water-cooled central chilled-water plants with meaningful annual runtime or utility demand exposure — hospitals, data centers, universities, large commercial offices, labs and manufacturing. Strong indicators include low delta-T, excess pumping, unstable chiller staging, high kW/ton, capacity that falls short on design days, or humidity and comfort complaints.
Yes. On new construction and retrofit central-plant pursuits, UCS serves as the dedicated controls and integration partner while the mechanical contractor keeps the equipment, piping and installation scope plus the client relationship and service opportunity. We are not looking to take over your customer.
Yes — Denver, Boulder, Fort Collins, Greeley, Longmont, Loveland and the wider Front Range, plus work across the Western U.S. UCS is Colorado-based and an official Siemens Value Added Partner.
Send us your plant type, your BAS and whatever trend data you have. We will come back with a fit or no-fit read — call (720) 282-5099 or request a screen.
