pv heater product presentation - techno · pdf filepv heater product presentation simple cost...

© by REFUsol GmbH 2013

PV Heater Product Presentation

� Simple� Cost effective� Reliabel� Transparent

© by REFUsol GmbH 201325/11/2013, Bollmann, PM

2

Agenda

� Market� Sales Arguments

� PV Heater vs. Thermal� Technology

� Logistics

� Services


5

Photovoltaics taken to the next level: Photovoltaic thermal energy

AE PV Heater:

� Use of PV beyond the feed-in tariff� Economical alternative to hot water heating

� Retrofittable for a variety existing heating systems



9

Agenda

� Market

� Sales Arguments� PV Heater vs. Thermal� Technology

� Logistics

� Services


10

Advantages of photovoltaics

� Flexible design: Orientation of the modules to the south, east or west; detached house, facade, garage, etc. (partial shading) thanks to 3 MPP trackers and module parallel operation (moduleMPPT)

� Aesthetic solution:Appealing flat design with homogeneous modules and full surface coverage instead of individual collectors

� No bureaucracy: Rooftop installation is not mandatory, because there is not compensation from the German Renewable Energy Act (EEG) and no coordination with the energy supply company for a grid connection


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Installation-friendly

� < 50 V direct current

� PELV (Protected Extra Low Voltage)

� Autonomous power can be provided� No danger in the event of a fire

� Wiring � Low losses, easy and flexible routing of

cable

� DC wiring: Standard PV cable with 2.5 - 6 mm² cross-section

Image source: photovoltaikanlagen.org, vbg.de


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Electronic unit and heating element

� Retrofittable in existing heating systems with standardized 1 ½ inch DIN flange

� Very high degree of unit efficiency >99% max.� Easy installation

(spring-tension clamps, screw fittings with sealing ring)

� Protection by single-fault tolerance of the electronics and integrated temperature sensors, limitation starting from 90 degrees

� Low-maintenance due to the low number of components and avoidance of wear parts

� No stress on the components due to high temperatures

� Electronics designed for a 20 year service life


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Estimation tool for easy system dimensioning

� Scenario: The goal is to completely switch off the heating in the summer

� 300 l accumulator, 200 l 40°C min. fill level, safety shut-off 95°C, 240 l 35°C daily consumption, 2250kWh/a yield, alignment to south

� Solar coverage of hot water preparation of 72% of annual amount. With an approximately 12-year-old 12kW oil-fired boiler, this saves around 340 l of oil/year over the next 25 years

� The amortization time is less than 12 years

� Future integration in REFUdesign


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Estimation Tool example Example:

In order to heat up a 300l accumulator from 10°C to 40°C, approx. 10 kWh are required at the heating element, which can already be achieved in March with 2.7 kWp on average

Rule of thumb: Volume * (Ttarget-Tout) * 1.16 = required energy


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In ongoing operation

� Hot water even in the event of a (grid) power failure

� Warm water from the sun

� No influence on the price of power from the German Renewable Energy Act (EEG) ("Good Investor")

� Detailed monitoring capabilities via REFUlog and REFUlog app


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Monitoring in REFUlog


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Agenda

� Market

� Sales Arguments

� PV Heater vs. Thermal� Technology

� Logistics

� Services


18

View examples

Solar collectorWarm water

Photovoltaic systemElectrical energy


19

Technical advantages: PV heater vs. solar thermal s ystem

Image source: omega-mauernutschelle.de, heizung-bad-shop24.de, Viessmann.com

� Cable instead of pipes:

Simpler, more affordable installation

Smaller cross-sections

Lower line losses � Existing water tanks can often be used,

because no additional heat exchanger is needed

� No filling and maintenance of the heat carrier medium

� No temperature-related stress on the components

� Fewer components

� No additional auxiliary power required� Yields thanks to immediately utilization of

diffused radiation - even in the transition time

� Simple system monitoring

PV Heater Solar Thermal


21

Agenda

� Market

� Sales Arguments

� PV Heater vs. Thermal� Technology� Logistics

� Services


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System design

� Parallel connection of 2-4 modules per MPPT (3 units); observe reverse current capability


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Economically optimized line losses

� For typical applications, the losses through 4-6mm² cross-sections are in the normal range

� 50% of losses occur with 100% insolation

Examples� PV: 2.2%*2000kWh

= 45 kWh/year� Thermal: 0.2W/K m = > 0.2*(70-

20K)*20m=200W *1500hours of sunlight = 300 kWh/year

Verluste nach Querschnitt und Leitungslänge-EU Einstrahlungsgewichtung-

0,00%

1,00%

2,00%

3,00%

4,00%

5,00%

6,00%

7,00%

20m 40m 60m

Ver

lust

leis

tung

4mm² 6mm²


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Device overview

Front side� 1: Connections for 3 photovoltaic strings

� 2: Display element� 3: Power-ON switch on device bottom side

Rear panel� 1: Ethernet connection

� 2: Screw-in heating element

� 3: Ventilation openings with drill marks

� 4: Supply openings


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Electronic assembly

Control terminals + sensors

Mounting flange

DC input1from panel

DC input2from panel

DC input3from panel

DC input throttle

DC input pole-reversal protection diode

Switch forON/OFF

DC output to the heating resistor

DC input cap

Input enable

6 LEDs

Relay output (changeover contact)


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Connection of the DC panel

DC input1 DC input2 DC input3

DC solar cable:

2.5 mm² to 6 mm²Red terminal = plusBlue terminal = minusMechanically fixed with cable ties on toothed rail

Check plus and minus of the string cable

using the integrated pole tester on the

circuit board


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Connection of an external temperature

Double PTC temperature sensorScaling up to 100°COperation up to 90°C

External temperature sensors are shown in REFUlog as Ext 1+2


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DC max. 50 V

Ethernet

Sensor1Controller

PV Heater overview layout

PE

MPPT1+Udc1+Output1

MPPT2+Udc2+Output2

MPPT3+Udc3+Output3

Relay

Voltagesupply

DC max. 50 V

Ethernet

Sensor1a+1bController

Ext 1+2

PE

MPPT1+Udc1+Output1

MPPT2+Udc2+Output2

MPPT3+Udc3+Output3

Relay

Voltagesupply

MPP regulationwith safety limitation for excess temperature


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Ethernet

Controller

PV Heater overview layout

PE

Internal DCvoltagesupply X16

� At least one DC connection must be active

� (Potential-free) Ethernet port for data communication and REFUlog

� Optional connection to a WLAN adapter (e.g. Netgear WNCE2001) via the local WLAN is also possible

� Relay output: programmable function, e.g. 2nd heating element or primary energy producer limitation; contact isolation for 230V, but it may only be operated with 24V for safety reasons

Relay


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Commissioning and parameterization via web interfac e

� Convenient network search and configuration of the IP

� Parameterizable relay output for the animation of external devices for hot water use, to switch off the primary heat producer or to provide status signals

� Enable switch for external control


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Legionella protection

Technical Regulation W 551 of the German Technical and Scientific Association for Gas and Water (DVGW)

� Small systems: Tank and central instantaneous water heater with utility water content of up to 400 liters and a content of 3 liters per pipeline

� A temperature of 60 °C should be maintained at the hot water outlet of the accumulator. With small systems the temperature of 60 °C should be considered a recommendation and is not a mandatory requirement. Therefore, operating temperatures of less than 60 °C are possible due to the low risk.

� Circulation systems are to be measured and operated in a manner such that the water temperatures in the system does not under cut the outlet temperature of the utility water heater by more than five degrees 0.3122.0 x 1

0.218.0 x 1

0.1315.0 x 1

0.07812.0 x 1

0.0510.0 x 1

Liters per meter of pipe length

Copper pipe outside diameter times wall

thickness in mm

Image source: e.wikipedia.org


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Heating element

� Retrofittable in existing heating systems with standardized 1 ½ inch DIN flange

� With the highly corrosion-resistant special nickel-iron-chromium alloy and the lower output/surface, calcification is prevented

� Installation should take place as close to the bottom in the hot water accumulator or utility water accumulator in order to utilize the maximum energy accumulation potential

� Max. permissible water temperature: 95 °C

� Use: Utility water, hot water� For many utility water accumulators, an enameled

connection flange is available for the inspection opening with 1 ½ inch inside thread

pufferspeicher.eu


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Heating element installation

� Determine the location of the threaded holes on the screw-in heating element

� Rotate the ring (inside of the housing) so that the screw holes line up with the threaded holes of the screw-in heating element

� Fit on the housing

� Fit four accompanying M4 x 16 screws and tighten in a crossing pattern


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Technical data

http://europe.refusol.com/fileadmin/user_upload/pdf/products/Technisches_Datenblatt_PV_Heater_EN.pdf


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Summary

EFFICIENCY

� More efficient than solar thermal systems

� Lower total installation expense� Very high degree of unit efficiency >99% max.

� High partial-load efficiency and utilization of diffused radiation

� No auxiliary power requirement

SAFETY

� Highest safety with single-fault safe design of the electronic circuit (overloading of the accumulator eliminated)

� Non-hazardous, safe-for-contact voltage level (fire department call)

RELIABILITY & DURABILITY� Maintenance-free

� Very reliability, low number of components, no components subject to wear

� Electronics dimensioned for service life of over 20 years


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FLEXIBILITY

� Flexibility in the installation location - does not have to be installed on the roof like with the German Renewable Energy Act (EEG)

� Highest flexibility in use with 3 MPP trackers

� Thin, elastic cable instead of thick pipelines

� No partial shade problems due to parallel connection of the models� Retrofitting in existing systems is both possible and beneficial

SATISFACTION� Hot water even in the event of a (grid) power failure, thanks to grid-independence

� Outstanding, detailed monitoring capabilities via REFUlog and REFUlog app

Summary


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