APPLICATIONS AND DEFINITIONS

(1)

HEAT PUMP APPLICATIONS

AND

DEFINITIONS

Per Fahlén

SP Energy Technology

(2)

APPLICATIONS OF HEAT PUMPS

• 1900s:

Refrigeration, need to chill food;

Survival:

→ very large application; chilled food comprises

y

g

pp

;

p

30-40 % of household energy use

Turnover: Sweden 10·10

9

_{, Europe 200·10}

9

_{, Global 1000·10}

9

_EUR

• 1940s:

Air conditioning, comfort

Wellbeing: Including productivity → large application

Voted innovation of the century in USA

Sales:

> 20·10

6

_{RAC per annum (explosive sales in China)}

• 1970s:

Heat pumps for heating, energy savings

Economy: Many alternatives for heating → limited application

Sales:

Sweden > 60·10

3

_{per year, > 600·10}

3

_{total number}

(3)

APPLICATIONS OF HEAT PUMPS

• Stationary

- Cryogenics

• Mobile

- Reefers road transport Cryogenics

- Freezers, refrigerators - Air conditioners

- Space heating

Reefers, road transport - Air conditioning (cars,

lorries, buses, trains, airplanes....)

p g

- Industrial processes

(4)

APPLICATIONS OF HEAT PUMPS

• Demand →

need to move heat from lower to higher temperature

• Hence need for heat pumps (chillers) →

basic heat pump theory

• Relation between demand and process →

t

system aspects

• Most commonly, end task is air cooling →

i

l

air coolers

• Common denominator:

Q

&

=

Q

&

_S

+

Q

&

_L

(condensation and frosting distinguishes air coolers from air

heaters)

(5)

APPLICATIONS:

Refrigeration and air-source heat pumps

• Display case air coil

• A/A heat pump

• Display-case air coil

• A/A heat pump

• Air coolers → all transport mechanisms must be

Air coolers → all transport mechanisms must be

considered

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HEAT PUMP APPLICATIONS

• Frozen and chilled food: Few alternatives (food hygiene, survival)

• Space cooling: Few alternatives (comfort, productivity)

Controlled temperature [°C] _{Heating and Hot Water}

p

g

(

p

y)

• Space heating and hot water: Many alternatives (comfort, productivity)

40

o

od g

60

Refrigeration and Cooling Heating and

Cooling w ater 20 ep fr oz en f o le d food m for t cooli n g Ho t w R oom em p eratu re 0 -20 _ozen and de e He at in g Ch il Co m He at in g Free cooling te -40 Fr o Application Free cooling

(7)

HEAT PUMP APPLICATIONS

• Outdoor air

“Unlimited” source

high air flows

-

Unlimited source → high air flows

-

High α, small Δt; frosting at t

_ao

< 5 to 7 °C, 2 < s < 4 mm

-

Thin coils → low Δp, high α, (developing flow)

-

Natural convection units → large area (the “ice stick”)

-

Fluidized bed

• Exhaust air

-

HRV, mandatory in Sweden since 1980

-

“Limited” source → fixed air flow

-

Moderate α, large Δt (often 20 K); 4 < s < 6 mm

-

Thick coils → long thermal flow path (high η

_t

)

-

Natural convection units → large area

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NOMENCLATURE: Definitions (1)

( )

• Direct (expansion) system DX (SS1897)

Direct (expansion) system, DX (SS1897)

A system in which the evaporator, condenser etc.

is in direct contact with the cooled or heated medium.

Only the heat exchanger wall separates the refrigerant

and the cooled or heated medium (see figure below)

Air or other fluid to Refrigerant system, R Air or other fluid to

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NOMENCLATURE: Definitions (2)

( )

• Indirect system (SS1897)

A system in which the evaporator condenser etc is

A system in which the evaporator, condenser etc. is

not in direct contact with the cooled or heated medium.

Note: An intermediate heat transfer medium, in this text denoted cooling or , g heating-agent, transports heat from the refrigerant heat exchanger to a

second heat exchanger between the brine and the cooled or heated medium. Only the heat exchanger wall separates the refrigerant and the cooled or y g p g

heated medium (see figure below).

cooling agent, ca heating agent, ha Refrigerant

system, R

Air or other fluid to be cooled or heated

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NOMENCLATURE: Definitions (2)

•

Brine, b (EN255)

Heat transfer medium that has a freezing point depressed relative to water. Comment: Brine is a water-based subgroup of cooling agents (see cooling agent)g p g g ( g g )

•

Condenser coolant, cc

Medium (fluid) that transports heat away from the condenser.

•

Cooling agent, ca (SS1897)

Medium (fluid) that transports heat from a heat source to a heat pump or from a cooled/refrigerated space to a cooling/refrigeration plant.

C f b i d l t d f i t ld id h t t f di

C.f. brine, secondary coolant, secondary refrigerant, cold-side heat transfer medium.

•

Heating agent, ha (SS1897)

Medium (fluid) that transports heat from a heat emitter to a point of use (e.g. from a condenser to a heating or hot water system).

C.f. heating water, heating air, hot-side heat transfer medium.

•

Refrigerant, R (SS 1897)Refrigerant, R (SS 1897)

Working medium (fluid) of a refrigeration (heat pump) process.

The refrigerant absorbs heat at a low temperature and a low pressure and rejects heat at a higher temperature and a higher pressure, usually through a change of state (liquid-to-gas, gas-to-liquid).

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NOMENCLATURE: Subscripts

p

• Subscripts: Medium, component, position, function

• Medium: a = air, w = water, b = brine, ca = cooling agent,

ha = heating agent, g = gas, l = liquid, s = solid

• Component: f = fan, cm = cooling machinery, cms = cooling

machinery system, sc = supplementary cooling, hp = heat pump,

hps = heat pump system, hs = heating system, sh = supplementary

heating, p = pump, ‘ = unsaturated, ‘’ = saturated,

• Position: 1 or i = inlet, 2 or o = outlet, 1 = condenser, 2 = evaporator

• Function: g = gas, l = liquid, s = solid, ‘ = unsaturated, ‘’ = saturated,

Function: g gas, l liquid, s solid, unsaturated, saturated,

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NOMENCLATURE: System diagram

y

g

& & & & & &

1 = condenser side 2 = evaporator side + y _W& cs Q Q_cms sc Q& 2 Q Q&₁ Q_hps Q&_hs cs = cooling system cms = cooling machinery o oled s p ace) uppl em ent ar y oo ling , sc e ated sp ace) M W&com em W& 2 ep W& 2 ef W& 1 ep W 1 ef W& sh Q& ehp W& system sc = supplementary cooling Heat pump, hp (c o _Su co _(he sc so u rce _Cooling machinery cm Heat transfer system,

cold side Heat transfer system

Supplementary heat, sh sink ehp W hp = heat pump hps = heat pump system hs = heating system H ea t

s cold side machinery, cm Heat transfer system, hot side Cooling machinery system, cms

Heat pump system, hps

Heating system, hs Cooling system, cs Hea t s _{sh = supplementary} heating e = electric m = motor f = fan p = pump

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HEAT PUMP EFFICIENCY ASPECTS

IMPROVE SPF BY OPTIMAL USE OF

FREE ENERGY AND DRIVE POWER, e.g.

• Reduce use/demand (load matching and storage)

• Reduce purchased energy (natural sources and sinks)

p

gy (

)

• Reduce drive energy for:

-

heat pumping (reduction of temperature lift)

p

p g (

p

)

-

heat transfer (heat exchanger design and control)

-

heat transport (system design and flow control)

t

i l

it (d i

d

t l)

-

terminal units (design and control)

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HEAT PUMP SYSTEM BOUNDARIES

cs

Q& Q&_cms

Q&

2

Q& _Q&₁ Q&_hps Q&_hs

+ ce) _ntary a ce) M W&com 2 ep W& W&ep1 sc Q sh Q& (c ool ed s p a Suppl eme n cooli ng, sc (heate d sp a M com em W& p 2 ef W& W&ef1 sh Q ehp W& Heat pump, hp ( sc t so u rce _Cooling machinery, cm Heat transfer system,

cold side Heat transfer system,

hot side Supplementary heat, sh

H t t h t sink

H

eat hot side

Cooling machinery system, cms

Heat pump system, hps

Heating system, hs Cooling system, cs Hea t ∑ = = n i ep i ep W W 1 1, 1 ∑ = = n j ep j ep W W 1 2, 2 Wehp

(15)

HEAT PUMP KEY NUMBERS

• Heat pump

• Carnot process

•

Q&1

Heat pump

T

₁

Q

h hp W Q COP 1 & & =

• Carnot process

hp e W& _,

Q

₁

W

hp e W _,

• Heat pump system

T

₂

Q

2 2 , 1 , , 1 , 1 p e p e hp e p e hps W W W W Q COP & & & & & + + + = 1 Q& 2 1 1 1 1 T T T W Q COP_C − = = p p p

• Heating or cooling system

2 1 2 2 2 T T T W Q COP _C − = = sh p e p e hp e sh sh p e hs Q W W W Q W Q COP & & & & & & & + + + ⋅ + + = 2 , 1 , , 1 , 1 η

(16)

SYSTEM DESIGN AND OPERATION

• Load matching by Control-On-Demand (COD)

-

Adapt the supply capacity → capacity control

Ad t th HVAC

t

-

Adapt the HVAC system

→

storage

• HVAC system design is crucial for

N t

l i k

-

Natural sinks

(free cooling)

-

Temperature lift

compressor (heat pumping)

⎥⎦

⎤ ⎢ ⎣ ⎡ − Δ ⋅ − − Δ ≈ Δ 2 1 1 1 2 2 1 2 T T T T T T T T COP COP hp hp

compressor (heat pumping)

-

Heat transfer

pumps fans

p

(

hp

)

e p hp e p h h W COP W COP COP

COP = − −1 ⋅ & , 1 + ⋅ & , 2

pumps, fans

-

Heat transport

heat losses, pumps, fans

hps e hp hps W COP COP , & =

heat losses, pumps, fans

-

Terminal units

- pumps, fans

hp e hp e hps e pW W W W R , , , − =

Parasitic drive

energy ratio:

(17)

EN STANDARDS

1. EN255-3Rev, 2007. Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors - Heating mode - Part 3: Testing and requirements for marking for sanitary hotPart 3: Testing and requirements for marking for sanitary hot water units.

2. EN378, 2000. Refrigerating systems and heat pumps - Safety and , g g y p p y environmental requirements.

3. EN14511, 2004. Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors for space heating and cooling

- Part 1: Terms and definitions. 4. - Part 2: Test conditions.

5 P t 3 T t th d

5. - Part 3: Test methods. 6. - Part 4: Requirements.

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EN STANDARDS (continued)

7 prEN14825 2010 Air conditioners liquid chilling packages and 7. prEN14825, 2010. Air conditioners, liquid chilling packages and

heat pumps, with electrically driven compressors, for space heating and cooling - Testing and rating at part load conditions and calculation of seasonal performance

and calculation of seasonal performance.

8. prEN15459, 2006. Heating systems in buildings - Data

requirements for standard economic evaluation procedures

l t d t t i b ildi i l di bl

related to energy systems in buildings, including renewable sources.

9. prEN15879-1, 2008. Testing and rating of direct exchange p , g g g ground coupled heat pumps with electrically driven

compressors for space heating and/or cooling - Part1: Direct exchange-to-water heat pumps.

10.SS-EN12102, 2008. Air conditioners, liquid chilling packages, heat pumps and dehumidifiers with electrically driven

compressors - Measurement of air-borne noise - Determination compressors Measurement of air borne noise Determination of the sound power level

11.SS-EN15243-2007, 2007. Ventilation for buildings - Calculation of room temperatures and of load and energy for buildings with of room temperatures and of load and energy for buildings with room conditioning systems.