Study: Hybrid systems for HVACs

The Energy Center of Wisconsin's report reveals that a hybrid HVAC system is more energy-efficient than a standard system, but is also more expensive.


The Energy Center of Wisconsin, with support from the U.S. Dept. of Energy and the University of Wisconsin Solar Energy Laboratory, spent more than a year working on hybrids and how they can save energy for HVAC systems. They found in their report that in the long term ground source heat pump (GSHP) as a hybrid is very cost-effective with an average rate of return of 10%. If they had fully invested in a GSHP without the hybrid, the return averaged about 3%.

However, going to a hybrid does have high initial costs, especially when you invest in a ground heat exchanger (GHX). Compared to the conventional HVAC system used now, it is more expensive, but not as expensive as a full investment in GSHP, according to the study by East Career and Technical Academy, a vocational high school in Las Vegas. The first cost savings were an estimated $1 million by going to a hybrid system.

Among the lessons learned from the study include cooling towers being at variable speed so they can shut off shortly after substantial cooling and boilers being placed downstream from a GHX and set 5 to 10 F cooler than the GHX temperature.

- Edited by Chris Vavra, Consulting-Specifying Engineer,

No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Choosing controllers: PLCs, PACs, IPCs, DCS? What's best for your application?; Wireless trends; Design, integration; Manufacturing Day; Product Exclusive
Variable speed drives: Smooth, efficient, electrically quite motion control; Process control upgrades; Mobile intelligence; Product finalists: Vote now; Product Exclusives
Machine design tips: Pneumatic or electric; Software upgrades; Ethernet advantages; Additive manufacturing; Engineering Leaders; Product exclusives: PLC, HMI, IO
This article collection contains the 5 most referenced articles on improving the use of PID.
Learn how Industry 4.0 adds supply chain efficiency, optimizes pricing, improves quality, and more.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Pipeline vulnerabilities? Securing hydrocarbon transit; Predictive analytics hit the mainstream; Dirty pipelines decrease flow, production—pig your line; Ensuring pipeline physical and cyber security