research seminar 8 june shire - warwick

A thermal transformer for recycling and upgrading waste heat

Research Seminar

8th June 2018

Waste-Heat Problem

ConclusionsResultsControlDesignTechnologyIntroduction Waste-heat problem

Opportunities

What is

waste heat?


0 10 20 30

Transportation

Process Industry

Residential

Commercial

Electricity Generation

<100°C

100-299°C

>300°C

Waste Heat (PWh)

52%The proportion of global

waste heat estimated to be

recoverable

37

26

68

Useful energy (PWh)

Unrecoverable losses (PWh)

Recoverable waste heat (PWh)

Waste Heat Availability

Source: BEIS Report, 2017

40TWh recoverable waste heat

from UK industry annually (DECC)


En

erg

y D

en

sity

(M

J/m

³)

Storage Temperature in degrees centigrade (°C)

Phase

Change

Materials

Sorption

Chemical Reactions

100 1000

1000

10000

Water

Industrial Process

Text

TextText

TextText Waste

HeatUpgrade

heat

Re-use Storage

Waste Heat Solutions

Upgrade

Requiring no additional energy input

The Technology


Exothermic


Adsorption

Solid

Fluid

Endothermic


Desorption

Solid

Fluid

Low Temperature

ReactorHigh Temperature

Reactor

CHARGING PHASE

COOLING HEATING


Thermal Transformation

Low Temperature

ReactorHigh Temperature

Reactor

DISCHARGING PHASE

HEATING HEAT OUT



Temperature

Pre

ssu

re

HEAT OUT

HEAT IN

HEAT OUT

HEAT IN

Tambient Twaste Tupgraded

Transformed Heat



Design


1

2

3

4

5

Review potential applications of waste heat recovery

Design, build and test a thermal transformation reactor

Disseminate work in energy transformation and storage technologies

Develop manufacturing methods for composite chemical adsorbents

Build a small-scale reactor to evaluate candidate materials

Aims


1. Project Scope

2. Material Manufacture

3. Design and build of

LTJ

4. Design and build of Thermal

Transformer

5. Impact

• Review

current

technologies

• Identify

waste-heat

problem

• Identify

temperatures

and select

salts

• Manufacture

composite

materials

• Analyse

thermal

properties

• LTJ design

• Manufacture

and

assembly

• Safety testing

• Testing

• Reactor

design

• Manufacture

and

assembly

• Safety testing

• Cycling

• Producing

project

website

Project Plan


Choice of reactants


• Improves thermal conductivity

• Increases surface area and porosity

for salt deposition

• Safe and cheap

• Reduces swelling and agglomeration

• Good heat transfer properties

• Ammonia systems are cheaper

as narrower-diameter piping

can be used

• Environmentally friendly

Working fluid Salt pair Composite material

Ammonia CaCl2 and MnCl2 Expanded Natural Graphite

• Operating temperatures

within range

• Low cost in comparison to

other salts

• Low hazard choice

Design Concepts


1. Large Temperature Jump Concept

2. Thermal

Transformer

Concept

Common requirements of both LTJ and Thermal Transformer

Safety CriticalHigh pressures &

temperatures, toxic gas

Modular DesignChange candidate

salts

Control SystemsInstrumentation and automation

Stage 1: Manufacture and Assembly

FabricationCustom parts fabricated and welded

within the School of Engineering

AssemblyMechanical and electrical components

assembled in the laboratory


This is a pointer

style COMPOSITE DISCSAmmonia flows through

solid-composite discs

containing reactive salts

OIL JACKETSOil flows through

an outer tube to

transfer heat

REACTOR

Stage 2: Salt Composite Manufacture


Large Temperature Jump (LTJ) experiments


Determine operating procedure for the

transformer

• Cycle time is important for industrial

application.

Applies a step-change in temperature

• Takes the material from one temperature to

another

Derive a relationship between temperature

and rate

• How quickly does the reaction happen for

an applied temperature?

Large Temperature Jump (LTJ)

Thermal Transformer

Valve switching

system

Valve switching

system

Huber oil baths

Huber chiller bath

Low Temperature

Reactor

High

Temperature

Reactor


Control



Hardware

7x Thermocouples

3x Pressure Transducers

2x Solenoids

12x Pneumatic Valves

3x Flowmeters

3x Oil Baths


Need for control

Undisturbed

test cycles

Human time

saving

Remote access:

presence in lab

not required

Reducing

human error

The Data

Acquisition unit

(DAQ)


Software

Bath Control

Solenoid Valve

Control

Stability Monitor

Data recording

Results



Large Temperature Jump (LTJ) Results

• Derived a relationship between the

operating temperature and cycle

time (to determine power output)

• Identified bounds of operation with

the selected salts


Thermal Transformer Results

40°CTemperature lift


Future work

Further testing Heat exchanger redesign Scaling

Conclusions


Conclusions

111 TWhUK annual industrial energy usage

44.5 TWhChemical, food and

paper processing annual usage costing

£2.2bn

£228mPotential annual savings

if 20% heat recycled


Source: Dalton et al, 2016

Conclusions

1

2

3 Successfully built and tested a system for upgrading

waste heat to higher, more useful temperatures, raising waste heat from 107°C to 147°C.

Built a LTJ rig and tested candidate chemicals over a

range of conditions. Produced hundreds of hours of test

results, showing effective operating conditions.

Developed a novel method for improving the properties

of salts by using an ENG matrix – improving

conductivity, mass transfer and salt stability.


33

Thank you for listening

Any questions?

research seminar 8 june shire - warwick

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