NREL is a national laboratory of the U.S. Department of Energy

Office of Energy Efficiency & Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC

This report is available at no cost from the National Renewable Energy

Laboratory (NREL) at www.nrel.gov/publications.

Contract No. DE-AC36-08GO28308

Combined Cooling, Heating, and 

Power (CCHP) System

Cooperative Research and 

Development Final Report

CRADA Number: CRD-14-570

NREL Technical Contact: Eric Kozubal

CRADA Report

NREL/TP-5500-72257

August 2018
NOTICE

This work was authored by the National Renewable Energy Laboratory, operated by Alliance for Sustainable 

Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding 

provided by the U.S. Department of Energy Office of Energy Efficiency, Building Technologies Office. The views 

expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. This report is 

available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

This report is available at no cost from the National Renewable 

Energy Laboratory (NREL) at www.nrel.gov/publications.

U.S. Department of Energy (DOE) reports produced after 1991 

and a growing number of pre-1991 documents are available 

free via www.OSTI.gov.

Cover Photos by Dennis Schroeder: (left to right) NREL 26173, NREL 18302, NREL 19758, NREL 29642, NREL 19795.

NREL prints on paper that contains recycled content.
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Cooperative Research and Development Final Report

In accordance with requirements set forth in the terms of the CRADA agreement, this document 

is the final CRADA report, including a list of subject inventions, to be forwarded to the DOE 

Office of Science and Technical Information as part of the commitment to the public to 

demonstrate results of federally funded research.

Parties to the Agreement: Be Power Tech, Inc.

CRADA number: CRD-14-570

CRADA Title: Combined Cooling, Heating, and Power (CCHP) System

Joint Work Statement Funding Table showing DOE commitment: 

Estimated Costs

NREL Shared Resources

a/k/a Government In-Kind

Year 1 $ 79,326.00

TOTALS $ 79,326.00

Abstract of CRADA Work:

NREL and Be Power Tech, Inc. (Be Power) will jointly develop a new combined cooling, 

heating, and power (CCHP) system that uses desiccants in combination with evaporative cooling 

and fuel cells. The combined system will have better economics and business case than a 

separate desiccant enhanced air conditioner and fuel cell system. The overall system is expected 

to become a net revenue generator by delivering power and air conditioning to a building while 

inputting natural gas and water. This development effort will revolve around adapting NREL’s 

desiccant cooling technology to work with Be Power’s proprietary system integration design for 

CCHP systems. The objective of the CRADA is to develop, then commercialize this CCHP 

system by jointly developing the system integration design, testing methods, and hardware for 

this system. The commercial name given to the CCHP system is BeCoolTM.

Summary of Research Results:

This report contains protected CRADA information, which was produced under CRADA No. 

CRD-16-570 and is not to be further disclosed for a period of five (5) years from the date it was 

produced except as expressly provided for in the CRADA.

NREL provided expert consultation and design assistance to implement NREL’s desiccant 

cooling technology into the CCHP system. The tasks were to co-develop a CCHP system using 

NREL’s design tools and expertise. The project was structured into four project areas based on 

NREL areas of support for Be Power Tech:
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

1. Detailed system modeling

NREL and BePower Tech engineers worked together to develop two heat and mass 

exchanger designs that are a part of the air conditioning system:

• A plate and frame membrane based dehumidifier that uses desiccant, water and a 

sweep air stream to cool and dehumidify a process air stream (HMX2) • An indirect evaporative cooler that accepts the dehumidified process air and cools it 

down to the desired delivery temperature (HMX3).

NREL performed thermodynamic modeling using the geometrical inputs provided by 

BePower Tech to predict performance and provide feedback on how to improve the

system’s design. The design assistance is described in section 2. This intelligence

provided BePower Tech the ability to construct two systems:

• A 1.5 ton prototype air conditioning sub-system used to inform the design of an 

integrated CCHP system • A 5 ton proof of concept CCHP system built to demonstrate the functionality and 

energy savings.

Figure 1 below shows the general process of the CCHP system co-designed by Be 

Power Tech and NREL. The fuel cell and regenerator system is combined with NREL’s 

evaporative liquid desiccant air conditioning concept (ELD-AC). In the diagram, process 

air is dried with HMX2 (dehumidifier) and sensibly cooled with HMX3 (indirect 

evaporative cooler). Liquid desiccant is regenerated by the combined fuel cell and 

regenerator, which provides the HMXs with concentrated liquid desiccant and water.

Oak Ridge National Laboratory tested the 5 ton system as a verification step of its 

performance1

. The measured performance showed the CCHP system to be a promising 

technology that can save energy and reduce the impact of air conditioning on the electric 

grid.

 

1 D. Betts, M. Ally, S. Mudiraj, M. Tilghman, M. Graham (2017). Oak Ridge National Laboratory Small Business 

Voucher CRADA Report: Natural Gas Powered HVAC System for Commercial and Residential Buildings. ORNL/TM2017/211.
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Figure 1. System diagram of proposed Be Power CCHP system. 

2. Heat and Mass Exchanger (HMX) design support

NREL used our existing heat and mass exchanger models from work performed in 2010-

20132,3 and used geometrical inputs from BePower Tech’s designs to determine 

performance. NREL then provided feedback to improve heat and mass exchanger 

design, which were incorpotated into BePower Tech’s designs. These designs were then 

implemented in the 1.5 and 5 ton systems described in project area 1 above.

The heat and mass exchanger models for the dehumidifier (HMX2) and sensible 

evaporative cooler (HMX3) were used in a reverse-design process. Initial performance 

was determined and model inputs were:

• Inlet air (30% outdoor air / 70% return air): 27.7°C dry bulb, 18.4°C dewpoint

• Outlet air: 15°C dry bulb, 10°C dewpoint

• 1 ton (3.5 kW) of cooling.

 

2 E. Kozubal, J. Woods, R. Judkoff 2012. Development and Analysis of Desiccant Enhanced Evaporative Air 

Conditioner Prototype. NREL/TP-5500-54755. 3 J. Woods, E. Kozubal 2013. Desiccant-Enhanced Evaporative Air Conditioner: Numerical Model and Experiments

NREL/JA-5500-56533. Energy Conversion and Management Vol. 65 January 2013 pp. 208-220.
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

The model was then used to determine performance parametrics to find the design space. 

For HMX2 (Figure 2), The model inputs were the layer thickness and thermodynamic 

quantities (e.g. conductivity, vapor pressure, and water diffusivity):

• Plastic plate (2 plates per channel pair)

• Membrane (2 membranes per channel pair)

• Desiccant film (2 per channel pair)

• Water film (2 per channel pair)

• Process side air gap

• Exhaust side air gap.

Figure 2. Depiction of the dehumidifier process and exhaust air flows as they pass through the 

parallel plate stack (HMX2).

L

H

process

air flow

exhaust

air flow

Wstack
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Figure 3. Shows and example of the trade-off of channel gap thickness, length and height vs the 

resultant air side pressure drop and number of channel pairs for HMX2.

The information shown in Figure 3 provided the design engineers with the necessary 

intelligence to choose a form factor for both efficiency and manufacturing 

considerations.

For HMX3, a similar design approach was used. Simulations were run using the 

following inputs:

• Vary process-side gap width between 2.3 and 3.1 mm

• Fix pressure drop at four levels

• Two exhaust-side gaps (1.5 & 2 mm)

• Fix wet-bulb effectiveness at 120%

• Solve for:

o Number of channel pairs required

o Plate length required

o Stack-up width
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Figure 4. Example of HMX3 stack up width as a function of pressure drop, exhaust air and 

process air channel gaps.

The information shown in Figure 4 provided the design engineers with the necessary 

intelligence to choose a form factor for both efficiency and manufacturing 

considerations. From inspection of the graph, the engineers are able to easily see the 

trade-offs between air gaps sizes, air-side pressure drop, HMX plate length and width.

Table 1 shows the specific case studies provided to the design engineers given their 

feedback on HMX2 manufacturing constraints.

Table 1. HMX2 air gaps, length, height and width study. 
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

3. HMX characterization.

The project concluded prior to funding this activity. No work was done for this 

activity.

4. Technology impact analysis. Be Power Tech will work with NREL to estimate

the environmental, grid stability improvement, cost reduction, and energy

independence benefits of the BeCoolTM system.

The project concluded prior to funding this activity. No work was done for this 

activity.

Subject Inventions Listing:

None

ROI #:

None

Report Date: 

23 July 2018

Responsible Technical Contact at Alliance/NREL:

Eric Kozubal

Name and Email Address of POC at Company:

Daniel Betts, DanielBetts@bepowertech.com

DOE Program Office:

Buildings Technologies Office, Fuel Cell Technologies Office

This document contains NO confidential, protectable, or proprietary information.