Environmental System Network Components

Component based environmental control networks are built up from entities in the systems components database. As each component is selected the user can alter its attributes to reflect the requirements of the current network. Each component is linked linked to one or more nodes in an up-stream component. Subsequently control logic may be associated with the component. For example, a typical layout for a boiler which would need to be translated into a system network description is shown below:

Database entities

ESP-r includes a database of environmental system components from which environmental system networks can be built. The entities in the database hold the definition of the control volumes (nodes at which an energy balance and optionally, where first and second phase mass balances are maintained), the matrix layout, the initial component attributes as well as the types of derived performance data to be exported.

As components are selected for use the user updates the component attributes for the specifics of the network in the model. The user then specifies the nodes in sending components to complete the network description.

Within the code, each component type is matched to subroutines which decode the attributes and matrix layout and generate the matrix coefficients for the solver.

The components included with ESP-r represent a variety of approaches to how components are represented, their thermophysical resolution and the level(s) of control which can be implied. There are thus multiple radiators, boilers and accumulators to choose from. Some components are represented as a single control volume while others may have more than a dozen. The number of attributes ranges from 4-132. Some components also include data for associated mass flow entities.

The following tables provide a summary of current system components. The columns are:

description

number of nodes (control volumes where energy (EB) and mass balances (MB) are resolved)

number of nodal connections (that other components link to)

number of component attributes (all include total mass, weighted average specific heat and a UA modulus for the component case)

derived outputs in addition to the component energy and mass balance

suggested type of flow component (if a flow network exists)

Air-side Components

Air side components are listed in the table below with a summary of attributes and indicators of the level of resolution.

Air side components
Name	Nodes	Connections	Attributes	Derived outputs	Flow type
centrifugal fan with flow control	1 EB+MB	1 dry/moist air	static rated absorbed power, mass flow rate, efficiency plus timestep mass flow rate	real & reactive power & internal heat generation	general flow inducer
AC fan with submerged motor	5 (EB+MB @ 2 solids & 3 dry/moist air)	3 (dry/moist air)	motor & casing mass, surface areas, specific heat, rated flow rate & power & velocity, efficiency plus timestep flow rate	none	none
air (dry & moist) flow multiplier	1 EB+MB	1 (dry/moist air)	2 flow ratios	none	none
air mixing box or converging junction	1 EB+MB	2 (dry/moist air)	3	none	general flow conduit
air duct	1 EB+MB	1 (dry/moist air)	hydraulic diameter, length, x-section area	none	general flow conduit
insulated air duct	4 EB+MB @ 2 solids & 2 dry/moist air	2 dry/moist air	layer mass, specific heat, thermal resistance at each face, heat transfer area, effectuve duct diameter, length, typical velocity	none	none
air duct damper with flow ratio control	1 EB+MB	1 dry/moist air	timestep flow fraction	none	general flow corrector
air flow diverger	3 EB+MB @ dry/moist air	3 dry/moist air	1 flow ratio	none	none
air flow converger	1 EB+MB	2 dry/moist air	none	none	none
spray/steam humidifier with flow rate control	1 EB+MB dry/moist air	1 dry/moist air	rated effectiveness, face velocity, area mode of operation plus timestep supply rate	vapour flow rate, heat demand, heat gain	power law mass flow
air cooling coil with flux control	1 EB+MB	1 dry/moist air	cooling duty	cooling output + real and reactive power	power law mass flow
air cooling coil with water mass flow control	1 EB+MB	1 dry/moist air	coil air & water heat transfer areas, face area, coil thermal resistance, tube diameter, inlet water temperature plus timestep flow rate	none	power law mass flow
air heating coil with flux control	1 EB+MB	1 dry/moist air	heating duty	heating output + real & reactive power	power law mass flow
air heating coil with water mass flow control	1 EB+MB	1 dry/moist air	coil air & water heat transfer areas, face area, coil thermal resistance, tube diameter, inlet water temperature plus timestep flow rate	none	power law mass flow
air duct electric heater	4 EB+MB @ 2 solids & 2 dry/moist air	2 dry/moist air	heater and casing mass, specific heat, heat transfer areas, cross sectional area plus timestep power input	none	none
cooling tower using the merkel model	2 EB_MB water and dry/moist air	2 water & dry/moist air	mass, packing volume, mass transfer area, vapour transfer	effectiveness, cooling power,NTUr	none

Heat exchanger and coil components

Heat exchangers and coils are shown in the next table. Again there are a variety of components on offer at different levels of resolution. Some are quite specific.

Heat exchangers and coils
Name	Nodes	Connections	Attributes	Derived outputs	Flow type
air/air plate heat exchanger	2 EB+MB	2 dry/moist air	total plate heat transfer area, net face area	none	power law mass flow
air cooling coil fed by WCH system	2 EB+MB dry/moist air & water	2 dry/moist air, water	number of rows, fins per meter, thickness, efficiency, spacing, diameters, face width & height	cooling energy, sensible cooling, condensate flow rate	power law mass flow
air cooling coil fed by WCH system	3 EB+MB mass, dry/moist air, water	2 dry/moist air & water	water mass, coil heat transfer areas, face area, thermal resistance, tude diameter	none	power law mass flow
air cooling coil water mass flow control	1 EB+MB	1 dry/moist air	coil face area, tube diameters, inlet water T, number of rows deep, parallel coil circuits plus timestep water flow rate	inlet air db and wb, cooling energy	power law mass flow
air heating coil fed by WCH system	3 EB+MB mass, dry/moist air, water	2 dry/moist air & water	water mass, coil heat transfer areas, face area, thermal resistance, tude diameter	none	power law mass flow
0.5 m length of 0.01 m dia heat transfer tube	3 EB+MB solid, dry/moist air, water	2 dry/moist air, water	air side & water side heat transfer area, coil face area, tube diameter	none	power law mass flow
air/water heat transfer tube	4 EB+MB solid, dry/moist air, water, water	3 dry/moist air, water, water	tube thermal resistance, air side & water side areas, free flow area, tube diameter and length, volume of air i tube	none	none
detailed heat exchanger model with hot fluid temp control	EB+MB 5xsolid, 5x dry/moist air	2 dry/moist air	cold fluid flow area, length heat transfer, hot fluid resistance plus timestep hot fluid temperature	none	power law mass flow
shell and tube type heat exchanger segment	3 EB+MB water, water, solid	2 water, water	mass of component, water in shell, water in tube, casing UA, conduction, number of tubes, tube radius, length, spacing, specific heat	none	none
generic 2-node fluid fluid heat exchanger with multiple flow regimes	2 EB water, water	2 water, water	hot and cold fluid mass, heat transfer coef, surface area, case UA, regime	heat transfer, number of units, effectiveness	none
generic 2-node gas fluid heat exchanger with multiple flow regimes	2 EB+MB dry/moist air, water	2 dry/moist air, water	hot and cold mass, heat transfer coef, surface area, case UA, regime	heat transfer, number of units, effectiveness	none
thermosyphon (NCHE) heat exchanger - SDHW systems	2 EB water water	2 water water	effectiveness coefficients, flow vs pressure coefficients, heat exchanger height	none	none

Thermostats

There are two component representations of thermostats. These can be used instead of the usual sensor location syntax to take into account sensor response issues.

Thermostats
Name	Nodes	Connections	Attributes	Derived outputs	Flow type
thermostatic radiator valve	1 EB solid	none	mass and specific heat, index of zone and (mounted-on) surface, conductance water to sensor, convective and radiant conductance to air/wall, radiator component id	none	power law mass flow
room thermostat	1 EB @ solid	0	component mass and specific heat, index of zone, viewed and mounted surface, conductances, acceleration heating	none	none

Boilers

There are multiple representations of boilers supporting a range of descriptive attributes and use cases.

Boilers
Name	Nodes	Connections	Attributes	Derived outputs	Flow type
non-condensing domestic WCH boiler	1 EB water	1 water	component mass, specific heat, case UA plus timestep energy supplied	none	quadratic law mass flow
non-condensing boiler & aquastat control (IEA Annex 10)	2 EB water, water	2 water, water	fuel mass flow rate, ratio of CO2 during operation, heat exchange water/flue, sensitivity coefficients, case heat loss, coefficients defining fuel plus aquastat setpoint and control signal	water exit temperature and flow rate, useful & consumed power, flow rates, burner time, efficiency & effectiveness & water heat input.	quadratic law mass flow
condensing boiler & ON/OFF control	2 EB water water	2 water water	gas firing rate & standby and heat content, efficiency coefficients running and standby, start-stop loss, upper temperature limit plus timestep control signal	on/off signal, gas consumption, efficiency water heat input standby loss	quadratic law mass flow
condensing boiler with modulation	2 EB water water	2 water water	full load firing rate, dump load fraction, gas heat value, boiler lock out time, case UA DHW draw schedule, cold water feed temp, upper boiler limit, lower limit of miudulating range coefficients for efficiency plus timestep control signal	on/off signal, gas consumption, upper temp, efficiency water heat input	quadratic law mass flow
boiler with explicit startup and cycle detail	2 EB water water	2 water water	similar to above plus purge times, fan rates, stabilisation times, ramp up gradiant plus timestep control signal.	on/off signal, gas consumption, upper temp, efficiency water heat input5	quadratic law mass flow

Water-side components

There are multiple representations of boilers supporting a range of descriptive attributes and use cases.

Water-side components
Name	Nodes	Connections	Attributes	Derived outputs	Flow type
water flow/temperature source for plant networks	1 EB water	1 water	minimum and maximum temperatures and flow rates plus timestep source temperature and flow rate	none	none
mains water temperature and draw profiles	1 EB water	1 water	method (Moore vs user), monthly mains temperatures	none	none
hourly draw profile	1 EB water	1 water	24 hourly values	none	none
stochastic hot water draw	1 EB @ water	1 water	nominal daily draw seasonal variation, phase shift, holiday periods, draw periods and attributes (47 in total)	6 types of flow rates	quadratic law mass flow
WCH pipe	1 EB water	1 water	pipe UA, Hydraulic diameter, length x-sectional area	none	general flow conduit
pressurised WCH pipe	1 EB water	1 water	mass, specific heat, UA to environment, hydraulic diameter, length cross sections area, pressure	none	general flow conduit
pressurised WCH pump	1 EB water	1 water	mass, specific heat, UA to environment, rated volume flow rate & absorbed power, efficiency, pressure plus timestep volume flow rate.	real and reactive power consumption	general flow inducer
WCH insulated water pipe	4 2x solid 2x water	2 water water	pipe layer mass, specific heat, resistance heat transfer areas, pipe diameter, length, air velocity	none	none
WCH pipe converging 2-leg junction	1 EB water	2 water water	3	mass, specific heat, UA to environment	general flow conduit
WCH pipe converging multi-leg junction	1 EB water	10 water	mass, specific heat, UA to environment, number of connections	none	general flow conduit
WCH water flow converger	1 EB water	2 water	working pressure	none	none
WCH water flow diverger	3 EB water water water	3 water water water	flow ratio	none	none
WCH flow control valve with flow ratio control	1 EB water	1 water	mass, specific heat, UA modulus plus timestep mass flow fraction	none	general flow corrector
WCH 3-port valve with flow ratio control	3 EB water water water	3 water water water	mass, specific heat, UA modulus plus timestep flow fraction	valve position	general flow conduit
domestic hot water radiator VO ~ 2 m^2	2 EB water water	2 water water	mass, specific heat, radiator exponent, nominal heat emission, supply & return temperatures, indices of zone and surface.	3	quadratic law flow
domestic hot water radiator VO ~ 2 m^2	8 EB 8x water	2 water water	mass, specific heat, radiator exponent, nominal heat emission, supply & return temperatures, indices of zone and surface.	environmental temperature, log mean temp difference, heat emissions between nodes	quadratic law flow
basic domestic radiator	2 EB water water	2 water water	mass, specific heat, surface area, heat transfer coefficients, indices of zone and surfaces	heat emissions to environment, mean radiator temp and environmental temp	quadratic mass flow
oil filled electric radiator with flux control	1 EB solid	0	mass, specific heat, radiator exponent, nominal heat emission, temperature, indices of zone and surfaces plus timestep supplied electrical energy	heat emissions to environment, mean radiator temp and environmental temp, real & reactive power	none
water cooler with flux control	1 EB water	1 water	mass, specific heat, UA to environment plus timestep cooling duty	none	quadratic law mass flow
flat plate solar collector	1 EB water	1 water	mass, specific heat, UA of case, directives for operational mode and tracking, location, collectors in series, area, fluid specific heat, fin efficiency, plate properties (21 in total)	1	power law mass flow
simplified flat plate solar collector	1 EB water	1 water	collector area & mass, coefficients for efficiency equations and angle corrections, flow rate, thermal capacity, heat loss coefficients, surface areas, position and angles, glycol % (36 attributes)	cosin of incident angle, incident solar, heat gains & loss	none
flat plate solar collector segment	1 EB water	1 water	mass, thermal capacity, heat loss coefficients, surface areas for cover & plate, efficiency, absorber & cover attributres, position and angles, tube spacing and diameter (22 attributes)	total heat loss, incident solar, plate temperature, mean collector temperature	general flow conduit
slab-on-grade hydronic floor	1 EB water	1 water	number of circuits, pipe diameter & spacing & conductivity & specific heat, associated zone & surface & layer	minimum & maximum flor temperature, wupply power, average fluid T and circuit length.	general flow conduit
cold water tank with 2 connections for TAC	1 water	2 water	mass, heat gain coefficient, specific heat of fluid	heat gain from room to tank	none

Heat pumps

There are multiple representations of heat pumps supporting a range of descriptive attributes and use cases.

Heat pumps
Name	Nodes	Connections	Attributes	Derived outputs	Flow type
cooling unit for TAC	3 EB+MB water water dry/moist air	2 water water	refrigerant inlet T, HE effectiveness, water pressure, nominal COP and COP generator and condensor coefficents, pump and condensor power, flow rates and temperature rise plus TAC cooling and dump signal	energy transfers, COP, energy rejected, air inlet T, pump and condenser fan power, cooling state, dump state	none
reversible water loop heat pump	2 EB+MB water dry/moist air	2 water dry/moist air	mass of pump, specific heat, UA of case, heating COP and coefficients, cooling coefficients plus timestep heat pump duty	heat pump duty, water heat transfer, air heat transfer, compressor poiwer, COP heating & cooling	power law mass flow
air source heat pump for WCH	1 EB water	1 water	COP method, coefficients for compressor & defrost cycle, attributes of pump, fan, controls (37 attributes)	heat output, COP, status, return water, real & reactive poiwer, defrost status	quadratic mass flow

Accumulators

Accumulators (water based thermal stores) have been a popular research topic in the ESP-r community. Thus the components database and associated code provide a range of options. There is likely to be some redundancy in the list below.

Accumulators
Name	Nodes	Connections	Attributes	Derived outputs	Flow type
WCH calorifier	2 EB water water	2 water water	mass, specific heat, UA of case, mass of water in tubes, coil internal and external heat transfer areas & coefficients	heat input to tank	none/td>
gas fired water heating for use with AIMS	3 EB+MB water dry/moist air dry/moist air	1 water	mass, specific heat, UA of case, burner capacity ON & standby, combustion & flue efficiency, excess air, molar fractions, DHW draw profile plus timestep firing signal	burner output, energy to water, fule consumption, air flow rates, temperatures of combustion and exhaust gases	none
gas fired water heating with storage	3 EB+MB water dry/moist air dry/moist air	2 water dry/moist air	mass, specific heat, UA of case, heat transfer to water, fuel mass ratios, excess air, efficiencies, water mass plus timestep firing signal.	signal state, fuel consumption, heat transer condensation kg	none
1-node tank for charging by fuel cell and adsorption storage	1 EB water	3 water	mass, specific heat, UA of case, element capacity ON and standby, DHW draw, operational flag plus timestep signal.	heater element output	none
1-node tank for charging by residential fuel cell	1 EB water	2 water	mass, specific heat, UA of case, element capacity ON and standby, DHW draw, operational flag plus timestep signal.	heater element output	none
3-node tank for charging by residential fuel cell	3 EB+MB water dry/moist air druy/moist air	1 water	mass, specific heat, UA of case, burner capacity ON standby, combustion efficiency, fuel molar fractions, DHW draw profile, operation mode plus firing signal	burner output, energy to water, fuel consumption, air flow temperature of gases	none
2-node tank with immersed coil	2 EB water water	2 water water	mass, specific heat, mass of tube node and tank node, length of tube & diameter & conductivity, coil diameter, coil height, shell diameter, coil type	heat transfer, heat coefficients at tube and tank	none
stratified storage tank with up to 100 layers	2 EB water water	2 water water	tank volume, dimensions, heights of inlets and outlets, conductivities, heat loss coefficients, fluid boiling temperature	average tank temperature, heat loss, internal time steps, mixing, number of mixed sections	none
stratified tank with one immersed HX	2 EB water water	2 water water	tank volume, tank dimensions, height of inlet & outlet, destratification data, node data, HX dimensions & pitch	average tank temperature, heat loss, internal timesteps, mixing state, heat transfer	none
stratified tank with two immersed HX	3 EB water water water	3 water water water	tank volume, tank dimensions, height of both inlets & outlets, destratification data, node data, both HX dimensions & pitch	average tank temperature, heat loss, internal timesteps, mixing state, heat transfer	none

TO BE DONE

Linkages

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Control

In ESP-r, most system components can have control imposed. Control follows the general ESP-r pattern of defining the location of the sensor, what it senses, defining the component to be actuated as well as a schedule (for each day type) of control laws (control logic). For example control applied to ....

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Some control actions are more complex and ...