House
[Residential loads (residential)]

The house object implements a single family home. More...

Functions
double	house::get_Tsolar (int hour, int month, double Tair, double Tout)
	This function calculates the solar air temperature based on the envelope construction, reflectivity of the color of envelope surface (assumed to be 0.75) and latitude adjustment factor based on time of day.
	house::house (MODULE *module)
	House object constructor: Registers the class and publishes the variables that can be set by the user.
int	house::init (OBJECT *parent)
	Map circuit variables to meter.
int	house::init_climate (void)
	Checks for climate object and maps the climate variables to the house object variables.
TIMESTAMP	house::presync (TIMESTAMP t0, TIMESTAMP t1)
	Updates the aggregated power from all end uses, calculates the HVAC kWh use for the next synch time.
TIMESTAMP	house::sync (TIMESTAMP t0, TIMESTAMP t1)
	Updates the total internal gain and synchronizes with the hvac equipment load.
TIMESTAMP	house::sync_hvac_load (TIMESTAMP t1, double nHours)
	HVAC load synchronizaion is based on the equipment capacity, COP, solar loads and total internal gain from end uses.
TIMESTAMP	house::sync_thermostat (TIMESTAMP t0, TIMESTAMP t1)
	The PLC control code for house thermostat.

Detailed Description

The house object implements a single family home.

The house only includes the heating/cooling system and the power panel. All other end-uses must be explicitly defined and attached to the panel using the house::attach() method.

Residential panels use a split secondary transformer:

		-----)||(------------------ 1    <-- 120V
		     )||(      120V         ^
		1puV )||(----------- 3(N)  240V  <-- 0V
		     )||(      120V         v
		-----)||(------------------ 2    <-- 120V

120V objects are assigned alternatively to circuits 1-3 and 2-3 in the order in which they call attach. 240V objects are assigned to circuit 1-2

Circuit breakers will open on over-current with respect to the maximum current given by load when house::attach() was called. After a breaker opens, it is reclosed within an average of 5 minutes (on an exponential distribution). Each time the breaker is reclosed, the breaker failure probability is increased. The probability of failure is always 1/N where N is initially a large number (e.g., 100). N is progressively decremented until it reaches 1 and the probability of failure is 100%.

The house model considers the following four major heat gains/losses that contribute to the building heating/cooling load:

1. Conduction through exterior walls, roof and fenestration (based on envelope UA)

2. Air infiltration (based on specified air change rate)

3. Solar radiation (based on CLTD model and using tmy data)

4. Internal gains from lighting, people, equipment and other end use objects.

The heating/cooling load is calculated as below:

Q = U x A x $ CLTD_c $

where

Q = cooling load for roof, wall or fenestration (Btu/h)

U = overall heat transfer coefficient for roof, wall or fenestration $ (Btu/h.ft^2.degF) $

A = area of wall, roof or fenestration $ (ft^2) $

$ CLTD_c $ = corrected cooling load temperature difference (degF)

$CLTD_c = CLTD + LM + (78 - T_{air}) + (T_{out} - 85)$

where

CLTD = temperature difference based on construction types (taken from ASHRAE Handbook)

LM = correction for latitude based on tables from ASHRAE Handbook

$T_{air}$ = room air temperature (degF)

$T_{out}$ = average outdoor air temperature on a design day (degF)

The Equivalent Thermal Parameter (ETP) approach is used to model the residential loads and energy consumption. Solving the ETP model simultaneously for T_{air} and T_{mass}, the heating/cooling loads can be obtained as a function of time.

In the current implementation, the HVAC equipment is defined as part of the house and attached to the electrical panel with a 50 amp/220-240V circuit.

Credits

The original concept for ETP was developed by Rob Pratt and Todd Taylor around 1990. The first derivation and implementation of the solution was done by Ross Guttromson and David Chassin for PDSS in 2004.

Billing system

Contract terms are defined according to which contract type is being used. For subsidized and fixed price contracts, the terms are defined using the following format:

    period=[YQMWDH];fee=[$/period];energy=[c/kWh];

Time-use contract terms are defined using

    period=[YQMWDH];fee=[$/period];offpeak=[c/kWh];onpeak=[c/kWh];hours=[int24mask];

When TOU includes critical peak pricing, use

    period=[YQMWDH];fee=[$/period];offpeak=[c/kWh];onpeak=[c/kWh];hours=[int24mask]>;critical=[$/kWh];

RTP is defined using

    period=[YQMWDH];fee=[$/period];bid_fee=[$/bid];market=[name];

Demand pricing uses

    period=[YQMWDH];fee=[$/period];energy=[c/kWh];demand_limit=[kW];demand_price=[$/kW];

Function Documentation

double house::get_Tsolar	(	int	hour,
		int	month,
		double	Tair,
		double	Tout
	)			`[inherited]`

This function calculates the solar air temperature based on the envelope construction, reflectivity of the color of envelope surface (assumed to be 0.75) and latitude adjustment factor based on time of day.

Returns:: returns the calculated solar air temperature

Definition at line 884 of file house_a.cpp.

house::house ( MODULE * mod ) [inherited]

House object constructor: Registers the class and publishes the variables that can be set by the user.

Sets default randomized values for published variables.

Definition at line 148 of file house_a.cpp.

int house::init ( OBJECT * parent ) [inherited]

Map circuit variables to meter.

Initalize house and HVAC model properties, and internal gain variables.

Todo:: use triplex property mapping instead of assuming memory order for meter variables (residential, low priority) (ticket #139)

Definition at line 306 of file house_a.cpp.

int house::init_climate ( void ) [inherited]

Checks for climate object and maps the climate variables to the house object variables.

Currently Tout, RHout and solar flux data from TMY files are used. If no climate object is linked, then Tout will be set to 74 degF, RHout is set to 75% and solar flux will be set to zero for all orientations.

Definition at line 252 of file house_a.cpp.

TIMESTAMP house::sync	(	TIMESTAMP	t0,
		TIMESTAMP	t1
	)			`[inherited]`

Updates the total internal gain and synchronizes with the hvac equipment load.

Also synchronizes the voltages and current in the panel with the meter.

Todo:: check panel main breaker (residential, medium priority) (ticket #140)

Definition at line 764 of file house_a.cpp.

TIMESTAMP house::sync_hvac_load	(	TIMESTAMP	t1,
		double	nHours
	)			`[inherited]`

HVAC load synchronizaion is based on the equipment capacity, COP, solar loads and total internal gain from end uses.

The modeling approach is based on the Equivalent Thermal Parameter (ETP) method of calculating the air and mass temperature in the conditioned space. These are solved using a dual decay solver to obtain the time for next state change based on the thermostat set points. This synchronization function updates the HVAC equipment load and power draw.

Definition at line 790 of file house_a.cpp.

TIMESTAMP house::sync_thermostat	(	TIMESTAMP	t0,
		TIMESTAMP	t1
	)			`[inherited]`

The PLC control code for house thermostat.

The heat or cool mode is based on the house air temperature, thermostat setpoints and deadband.

Definition at line 510 of file house_a.cpp.

House [Residential loads (residential)]

Functions

Detailed Description

Function Documentation

House
[Residential loads (residential)]